He is a lightweight professional boxer and one of the core members of the Kamogawa Boxing Gym. He, along with Kimura Tatsuya, are known to have been scouted into boxing by Takamura Mamoru, an individual they swore to defeat but eventually came to admire.
His surname is Aoki. In Japan, surnames are listed before given names.
Aoki is the oldest brother of his nine siblings and was starred in a TV show about his family called "Heartwarming Special Presents: The Hectic Life of an 11-Person Family". He was helpful to his family by cooking meals for his whole family. Aoki would be forced to leave the family because his dad got very sick and ending up running a ramen shop called "Chūka Soba", making use of the natural cooking talent. The ramen shop expanded to three stores thanks to his recipes. Aoki used his money to fund his sibling's school fees and never thought twice about helping his siblings.
Aoki had a delinquent past with long-time friend and schoolmate Kimura Tatsuya. Together they would pick fights and wreak havoc frequently until he met and attacked Takamura Mamoru in an arcade. Takamura was given a concussion by Aoki by kicking his head into an arcade screen, but Takamura retaliated and defeats Aoki, leading him and Kimura on a path of revenge- their goal being Takamura in the end. After several failed attempts Aoki and Kimura found their way to Kamogawa Boxing Gym where they find Takamura. There, they were introduced to boxing, and trained with a single goal of defeating Takamura in mind. Upon their winning of their individual debut matches the two realised that Takamura was no longer just their 'goal' but their inspiration and idol as well.
Sometime after a KO loss, Aoki was told by Kimura that he loss because of his weak jaw. Aoki then began wondering what he can use against another's jaw. A frog then jumped on his hand, which Aoki noted how, just like him, frogs can not fly. However, if it tried hard enough, maybe it would grow wings. He then thought of the Frog Punch, which gave him confidence and used it in his next match.
In the anime, Aoki watched Makunouchi Ippo and Miyata Ichirō's spar. After the spar, he introduced himself to Ippo. On Ippo's first day at the Kamogawa Boxing Gym, Aoki and Kimura Tatsuya attempted to train him, but was stopped by Kamogawa Genji. While Ippo was training, Aoki served Ippo and the others ramen at his restaurant. Before the second spar, Aoki acted as Miyata's sparring partner. When the spar rematch arrived, Aoki watched the spar between Ippo and Miyata.
When Yagi Haruhiko revealed Ippo's pro debut match to be Oda Yūsuke, Aoki suggested it would be an easy fight. At the Chūka Soba, Aoki served Ippo and the others ramen, he then did fortune telling with cards, he pulled out a card that showed Ippo would win. Aoki was Ippo's sparring partner for training against Oda. Aoki watched Ippo's fight against Oda and celebrated after Ippo's first win.
After sparring with Ippo, Aoki celebrated Ippo's first year in the Kamogawa Boxing Gym at the Chūka Soba. Aoki explained how his Rookie King Tournament went, however he got upset when Takamura pointed out how his opponent who beat him in the first match wasn't good. When Jason Ozuma was announced as Ippo's first opponent in the East Japan Rookie King Tournament, Aoki and the others believed it to not be his real name until his profile was shown to be American. As Ippo was not used to fighting black boxers, Aoki painted himself black, which successfully eased Ippo as they got ready to spar. Aoki watched the match between Ippo and Ozuma.
With Ippo being fired up from watching Miyata's match, Aoki and Kimura sparred with him. When Takamura saw Ippo's flare up, thinking about a girl, Aoki warned him that he would not go up in the world thinking only about girls. He explained to Ippo that he had girl troubles before. After watching a tape of Hayami Ryūichi fighting, Aoki told Ippo that he wanted to help him defeat Hayami by doing roadwork and sparring with him.
Aoki attended the training camp. On the final night at the training camp, Aoki wished to get a Japanese title belt as he watched fireworks. When he and the others got back to the gym, Yagi showed everyone the poster of Takamura's match against the Japanese middleweight champion and Ippo's match against Kobashi Kenta.
Aoki attended Ippo's match against Kobashi, and Takamura's Japanese middleweight title match against Yajima Yoshiaki. When Takamura went down, Aoki and the other's cheers helped Takamura stand up. After Ippo's win and Takamura wins the champions belt, Aoki celebrated along with everyone.
Ippo, Takamura, and Kimura went to the Chūka Soba to talk about Aoki's match. Aoki got depressed when Takamura claimed that he should not be nervous, since he is good at making ramen, so he would have no worries about retirement. He became even more depressed when Ippo felt better knowing that Hayami's match was before Aoki's. When Aoki's match began, despite being nervous before it started, Aoki ultimately won the match. Later, when Miyata visited the Kamogawa gym, Takamura made fun of Aoki and how the girls stood up and left before his match began.
When Ippo wanted to learn how to counter against Hayami's short uppercut, Aoki was his sparring partner, where he would throw uppercuts for Ippo to counter with a hook. At the Chūka Soba, After seeing the East Japan Rookie King Tournament being covered in a magazine, with Ippo's section being the smallest, Takamura claimed that Ippo was the Manbaken. Aoki thought otherwise, making Takamura decide to set a bet. Kimura chose Hayami, Takamura chose Miyata, and Aoki was forced to go with Ippo. Aoki, along with Takamura and Kimura visited Ippo's home, where, despite having a fever, Ippo trained with Aoki. Aoki attended the match between Ippo and Hayami, with the match ending in Ippo's win.
Aoki watched a tape recording of Miyata's match against Mashiba, which Miyata lost and Mashiba fouled. Aoki was angered at the result and believed Ippo's match against Mashiba is for Miyata's revenge. When Aoki and Kimura returned to the gym, they were thrilled to see Ippo hitting a sandbag and seemingly not bothered by the outcome of the match. However, it was revealed that he was hitting the sandbag for too long, breaking his fists and unable to use the for a week by Kamogawa. Aoki was informed by Takamura that a girl that Ippo liked was actually Mashiba's sister, prompting Aoki to tease Ippo about it the next day and made fun of him for thinking he was to protagonist of grief. Fujii Minoru then arrived, revealing the Mashiba family's history. Hearing the story, Aoki agreed that if it was for the sake of his own sister, he would feel fine to win even if he would have to cheat. When Kamogawa allowed Ippo to use his fists, he had Aoki and Kimura spar with him. Before the match between Ippo and Mashiba, Aoki wished to Ippo good luck. Aoki then watched the match, which ended in Ippo winning. Aoki remembered the bet, however he was knocked out by Takamura.
When a man visited the gym looking for Ippo, who eventually appeared, he revealed himself as the West Japan Rookie King. Hearing this name, Aoki remembers him as he was called "Rocky". When Sendō accidentally revealed that he can use the Smash, Aoki was surprised. Aoki informed Sendō that Ippo was not in condition to fight after Sendō kept asking despite his fist injury.
The next day, after Kamogawa left for Thailand tog get boxers for Takamura to fight, Takamura became fired up and wanted to spar. Eventually, Sendō decided to spar despite Aoki warning that Takamura was six classes higher. Aoki then witnessed the spar where Sendō used the Smash before getting knocked out. After Sendō woke up, Aoki had Kimura use his vehicle to drive him to the airport for Osaka. On his way to work, Aoki talked with Ippo, who explained to him that the number one Judoist was his doctor. When Aoki saw the doctor, Yamaguchi Tomoko, he ran to a phone booth. Later, Aoki teased Ippo about him and the female doctor with Kimura and Takamura.
Aoki later watched videos of Sendō fighting, which would sometimes cut to adult scenes thanks to Takamura. Two days before Ippo's match against Sendō, Aoki arrived to the Ishino Boxing Gym in Osaka along with the rest of the Kamogawa gym. Aoki watched as Ippo sparred with lightweight class Komori, which ended early due to Ippo being unable to hit with his right. When Takamura gave Ippo advice, Aoki downplayed it, causing him to take a punch to the face by Takamura. Aoki wanted to apologise to Takamura until he found an adult magazine that Takamura bookmarked where a female in Osaka wanted the reader to call her. When the day of the match arrived, Aoki went to the Osaka Prefectural Gymnasium and watched Ippo fight Sendō, where Ippo would later win, becoming the Rookie King. Aoki attended Ippo's celebration party at the Plum Village, which ended early due to Takamura knocking out Kamogawa.
The Kamogawa gym had a promotional event coming up starring Aoki, Kimura, and Takamura having a match on the same day at the Kōrakuen Hall. Because of this, a big group of newcomers joined the gym. This caused Takamura to test them by making them partake in the roadwork the gym members do, which Aoki also partook. At the end, only one remained in the end, Yamada Naomichi, later nicknamed "Geromichi" due to him throwing up on Ippo after the roadwork and also was a fan of Ippo, discovered when Aoki looked in his wallet. Aoki and Kimura then sparred each other to prepare for their upcoming match. When Aoki's match against the fifth ranker in the Philippines, Arman Garcia began, Aoki defeated him by knockout in the seventh round. Now ranked fifth, Aoki became excited about the feeling of a chance at the champion belt if he defeats four more fighters. One month later, Aoki watched Ippo's match against the fifth ranker in the JBC, Okita Keigo, which ended in Ippo winning.
Due to a new boxing boom, a television station visited the Kamogawa gym in order to capture how the youth put their hopes in boxing. The interviewer was the idol, Kumiko Morita. After the event, the television crew left the gym. When the event got shown on television where Aoki and the others got interviewed, Aoki noticed that Ippo sent a challenge to the champion Date over a national broadcast. He also witnessed seeing the interview at the Otowa Boxing Gym where Russian boxer Alexander Volg Zangief claimed to want Date's belt. When Yamada left the gym for his Pro Test, Aoki went along with him to the Kōrakuen Hall. When Yamada won the Pro Test match, Aoki, Kimura, and Takamura "lectured" two people that were making comments about Yamada while he was fighting.
When Aoki came back to the gym, Kamogawa and Yagi announced the entry list for the Class A Tournament where there were eight people signed up in his lightweight class. Takamura then invited Aoki to go to the annual training camp to prepare for the tournament. At the training camp, due to Ippo's mother's illness, Ippo could not go to the training camp nor has he visited the gym in a week, making Aoki and the others to speculate that Ippo may be retiring. When Aoki and the others returned to the gym, they were surprised to see Ippo there and that he was not retiring. While Ippo was training to go against Saeki Takuma, he planned to use his legs, however, Aoki believed that the rhythm Ippo chose was not going to work.
On the day of the first round of the Class A Tournament, Aoki had his match against Bull Ushida. On the sixth round, Aoki decided to use his new technique that he wanted to save for the finals, the Frog Punch on Bull, causing Bull to get knocked out and Aoki winning the match. With Aoki, Kimura, and Ippo having won their matches, they went to the Gaiant Echo karaoke with Takamura to celebrate. There, Takamura decided to sing the song "Champion". Aoki was shocked when he saw Hayami in the video as the song played. Aoki then joined to sing the song with Takamura and the others.
After leaving the karaoke, Aoki went to Takamura's home with Ippo and Kimura, where Takamura revealed that Yamada would be moving away from Tokyo in two days. A farewell party customary of the gym for retiring boxers was then planned for Yamada. The next day, Aoki went to the basement of the Kamogawa gym for the farewell party along with Ippo, Takamura, and Kimura. When Yamada arrived to the basement, Aoki, Kimura, Ippo, and Takamura fought him in a spar. After the farewell party, Aoki saw Yamada as he left the gym to leave Tokyo. Later on while training, Aoki and Kimura realised just how close Ippo was to surpass them, which motivated them to keep on training to obtain the JBC titles as well. The next day at the gym, Ippo, wanting to do something other than encouraging the duo, sparred with them while mimicking their upcoming opponents fighting style.
When the day of the Class A Tournament semi-finals arrived, Aoki's match against Jackal Itō began. Aoki lead the match in points up to round four. Noticing how he has not widened his point lead, he attempted to finish it with his Frog Punch, but it got countered, sending him to the canvas. After getting up, Aoki did the Frog Punch again, but this time he turned it into a feint and knocked down Jackal with a hook. Eventually, Aoki was hit by a right hook that passed his guard, knocking him down. With Aoki's legs unable to let him get up, he lost the match, losing the tournament. After the match, Aoki and Kimura were visited by Ippo and Takamura in the locker room. Aoki and Kimura acted as if the lost did not bother them before encouraging Ippo to win as they leave. Later that night, despite their act, Aoki and Kimura were upset about the way their matches went, and spent the night reflecting on the events.
Aoki, Takamura, and Kimura visited Ippo at the Swimming Club where they found him doing squats in the water. Aoki and Kimura attempted the training, but were unable to keep up with the resistance from the water after a few minutes. They were surprised that Ippo had been doing it for a week, blindly trusting Kamogawa without knowing what the actual move was. Aoki then saw the technique that Ippo was training for called the Gazelle Punch. As Aoki witnessed Ippo going through the harsh stamina training sessions set by Kamogawa and showing signs of being overworked, he warned Ippo that boxers can not show their full strength if overworked. Later, Aoki requested for Ippo to succeed in the Class A Tournament where he failed. Aoki later attended Ippo's match against Volg, where Ippo would later win.
Aoki, along with Kimura and Takamura checked on Ippo at the Kawai Hospital. After greeting him as he just woke up, they proceed to take his urine, as they had done for the past three days until Ippo runs out the hospital room in fear. When nurse Reiko left, Aoki, Kimura, and Takamura ask her about the group date they had set, and became excited when she confirmed that she gathered three other women for the date. When Ippo got out of the hospital, he was invited to the group date with Aoki, Kimura, and Takamura. The four boxers then had a bowling competition where the first place winner would be able to pick first for the woman they wanted to go out with. Aoki won first place in the end and picked Tomiko. Aoki's date with Tomiko proved to be successful, as Tomiko stayed with Aoki through the night and answered the phone when the Kamogawa gym tried to call him to make fun of him if his date rejected him. Aoki later attended a training camp with the others at the Izu for his upcoming match.
For Takamura's Champion Carnival title defence against Tamaki Atsushi, Aoki cheered for him, where Takamura would later win. Later, Aoki brought Tomiko to the Kamogawa gym so she could meet the place where he trains. Aoki then had Tomiko use tarot cards to see how Ippo's match against Date would go. The fortune telling session then ended before the result came up due to Kamogawa interrupted it and kicked them out. Aoki then watched Ippo's match against Date, which ended in Ippo's first loss. After the match, Aoki and Kimura asked Takamura to consider Ippo's feelings on his first loss, instead of rubbing it in. When Takamura met Ippo, he congratulated him, surprising everyone. But immediately after, used their reactions as an excuse to humiliate Ippo, and Kamogawa kicked him out of the room.
A week after Ippo had not come to the gym so that his injuries could heal, Aoki and Kimura felt like the environment around the gym changed as it felt like they were compelled to work while he is there. That night, when Aoki, Takamura, and Kimura walked to Takamura's house and noticed Ippo still watching the video of his loss against Date, Takamura decided that they should kill some time at a game centre, not wanting to go to the "haunted room". Later, when Ippo came back to the gym, he heard from Fujii that, due to Volg's second loss in a row, the Otowa gym was cutting ties with Volg, with him getting sent back to Russia the same day. Aoki remembered a worse story where a southeast Asian boxer lost and was sent home the same night on a cargo ship. With Ippo disappointed by the event, Takamura handed Ippo money which came from Aoki's wallet for a taxi to the Narita Terminal 1, making Aoki angry.
Later, Aoki and Kimura informed to Ippo that Yagi flew back to Japan after getting three opponents for the trio's comeback matches. Takamura then wondered who was going to be the main event, with Ippo wanting to let Aoki or Kimura be the main event, the two began arguing over it. Takamura then decided to settle the match order by drawing straws. After the three drew straws, Aoki was decided to be the main event. Aoki excitedly called Tomiko about it, however, as she told everyone at the hospital about it, Kamogawa entered the gym and revealed the actual order being Aoki as the opener and Ippo as the main event.
Aoki later entered the gym after telling Tomiko that he was in fact not the main event. Aoki then revealed the frog-themed robe that she made for him. Aoki ran off laughing when everyone lied and said that it looked good on him. Later, while Ippo partook in Kamogawa's mitt training session, Kamogawa collapsed to the mat when he caught one of Ippo's punches with his mitt. Aoki went to the Kawai Hospital, where Kamogawa was taken. The doctor informed everyone that he fell because of overwork and to let him rest for two to three days. On the second day, Aoki warned Ippo that with Kamogawa away from the gym, Takamura may prank them. Takamura began his pranking by telling Aoki about who won in a wrestling match, performing a jumping DDT on Aoki and kicking his face. When Kamogawa came back to the gym after being released from the hospital, Aoki was overjoyed as Takamura was unable to continue his antics.
When the day of his comeback match arrived, Aoki got into the ring with his new frog-themed robe. The match against Snake Thomas then began. Aoki went through the match with the feeling of having Tomiko to protect, driving him to win easily by knockout. Aoki then watched Kimura's and then Ippo's matches where they both won.
Aoki was visited by Ippo and Takamura where they found an album with pictures of Aoki and Kimura during their delinquent days. Aoki, Ippo, and Takamura then head to Kimura's home where they were informed by his mother that he has a fever. When they entered Kimura's room, Aoki told him that he believed that it was not a bad thing to try his best for a woman when the depressed Kimura expressed his beliefs that boxers don't need women. When Ippo made Kimura's fish faint by feeding her his aspirin, Kimura screamed her name as "Reiko", making Aoki realise that Kimura was not over Reiko. Ippo then pointed out that Aoki and Kimura looked like they got along well in their delinquent photos, wanting to know details about their past. Aoki and Kimura then told Ippo their past as delinquents up to when they won their debut matches. After telling Ippo their story, Takamura teased the two by offering them to hit him, causing Aoki and Kimura to retaliate and hit Ippo for starting it.
When Aoki learned that the Naniwa Boxing Commission agreed to let Ippo fight Sendō two months after Sendō's second title defence, Aoki suspected that they were underestimating Ippo. Kamogawa then announced a training camp for the gym, making Aoki excited as Kamogawa warned that it will be hard. When it was time to leave for the training camp, Aoki and the others got ready for the beach. However, Aoki was disheartened to learn that the gym would be going to the mountains where Kamogawa's friend is letting him use his pension. Upon arrival to the Pension Yoshio, Kamogawa's friend and rival, Nekota Ginpachi greeted everyone, knowing Ippo and Takamura while mistaking Aoki and Kimura as non-Japanese boxers. Shinoda Tomoyuki then took Aoki, Kimura, and Ippo to do roadwork in the woods after Nekota warned them of bears. As Aoki underestimated how hard it was to run in the woods, everyone noticed a bear behind them, resulting in Aoki and the others to run back to the house in fear. When Aoki mentioned running into a bear, Nekota offered something to keep bears away the next day.
The next day, Aoki wore a bell as a bear repellent and did roadwork with Ippo, Kimura, and Takamura. As Aoki, Kimura, and Ippo believe the bell to be keeping the bears away, Ippo was attacked by a bear, causing Aoki and Kimura to rush back to the house to inform the others. However, as they explain what happened, Ippo ran out of the woods with the "bear", which was actually Nekota's dog Hachi. Kamogawa announced to everyone that they would be staying at the pension for a week and had Shinoda train Aoki and Kimura. The duo began their training exercises, with their main exercise being doing squats in the river. When Aoki was done with his training and went back to the house, Ippo told him that he heard of a way of punching without punching, which Aoki thought was hard to believe. Later, Aoki listened as Kamogawa explained to everyone about Sakki, a feint with soul, and showed them pictures of him and Nekota in their boxing days. When Takamura decided to show Ippo the Sakki in a spar, Aoki claimed to have figured the Sakki out. When he tried it against Takamura in the ring, he got into the Frog Punch position and asked if Takamura could see him jumping as he stayed still. Takamura then kicked Aoki for joking around. Aoki then continued training for the day.
On the final day of the training camp, Aoki continued to train by doing squats in the river. That night, as Takamura had not come back yet, Ippo wondered if Takamura could defeat a bear if he ran into one, however Aoki deemed it impossible. When an injured Takamura returned and claimed to had knocked out a bear, Aoki and the others did not believe him. Aoki's thoughts changed however when Nekota brought out bear nabe and Takamura began crying when the bear that Nekota killed matched the description of the bear Takamura knocked out and let live. The next morning, with the Kamogawa gym members about to leave to go back to Tokyo, Aoki said his goodbyes to Nekota. When Aoki returned to the gym and a boxer named Shigeta Akira requested to spar against Ippo, Aoki watched and tried to give tips to Ippo as he fought a Southpaw in the past, but he lost in a short amount of time so he couldn't help. Later at the gym, Fujii accidentally revealed that Takamura would be having a world match, shocking Aoki, who then listened as Kamogawa explained that it would be a junior middleweight world ranked match that, if Takamura were to win, he would be a contender to the world title.
Fujii then introduced Aoki and Kimura to sports writer Iimura Mari. Aoki was quickly irritated when she asked for him to act naturally and to not give her special treatment because of her gender. After learning that she shows little to no interest in Japanese boxers, deeming the champions as 4-6 rounders, Aoki asked if she would consider Takamura the same league, which she then admits that he was an exception. When Fujii and Mari left the gym, Aoki and Kimura were shocked that a woman came into the gym and Takamura ignored her, deducing that it was about the world match announcement. Later while Aoki, Kimura, Ippo, and Takamura were doing roadwork, Aoki and Kimura hoped for knockouts for their matches. Takamura claimed that when his match begins, everyone will forget about everything that happened, making the duo irritated.
When the day of the matches arrived, Aoki went to the ring after Kimura won. Aoki fought against Boy Allade. In the third round, Aoki and Boy get into a close ranged hitting match until the towel was thrown, resulting in Aoki's win. Aoki then watched Takamura's match with Tomiko. Aoki was surprised when he saw Takamura entering the ring with bear skin on. After Takamura won the match, Aoki celebrated with everyone at the Sugar Ray. Later, Aoki returned to the gym and discovered that Nekota stayed at the gym and began teaching others. Eventually, Nekota left by a delivery truck service back to the mountains, with Aoki saying his farewells.
A month and a half before Ippo's title match against Sendō, Ippo was instructed by Kamogawa to go to five different gyms to fight five boxers from different weight classes for five days. Aoki agreed to drive Ippo to the gyms with a car lent from Yagi. On the fifth day and after Ippo knocked out the fifth boxer, Aoki and Ippo went back to the Kamogawa gym where Ippo wanted to spar against Aoki. Aoki remained standing after the spar ended, stopping Ippo's fifth knockout streak. When the match poster for the match was put on the gym's windows, Aoki expressed how would be satisied with just one title match, then got angered when Takamura acted like he did not know Aoki and Kimura did not have title matches in the five years they had been boxing. On the day of ippo's title match, Aoki went to the Kōrakuen Hall to watch the match. While getting to the seating area, Mashiba bumped into Kimura. While a fight between the two was about to start, Aoki held Kimura back while Kumi held Mashiba back. Kimura then thanked Aoki for saving him from getting beaten up. Aoki then watched the title match, and during round two, he began stomping his feet with the audience, cheering for Ippo. After Ippo won the match on the seventh round and became the JBC featherweight champion, Aoki, Takamura, and Kimura took Ippo to his home. A few days later, Aoki went to the Sugar Ray for Ippo's celebration and birthday party.
At the Kamogawa gym, Kamogawa revealed for the annual Champion Carnival, Kimura would be fighting the JBC junior lightweight champion Mashiba. Aoki was ready to help Kimura by sparring with him, however Kimura left the gym to seek help from someone he claimed to know would be able to help him. At the Chūka Soba, Aoki met Kimura, who he had not seen for a while since he left the Kamogawa gym. After a short friendly argument, Kimura left. After Ippo received tapes of Mashiba's spars from Mari, Aoki requested to deliver the tapes himself. Aoki met up with Miyata to have him deliver the videos. Aoki then asked if Kimura can win, however Miyata could not answer. Aoki mentioned how he saw when Kimura came by at his shop that Kimura was thinking about retirement as Kimura and him are twenty-three years old, ageing fast in their profession, and lost many chances for a title. Aoki then did a Dogeza, pleading for Miyata to help Kimura have a match he will not regret. After two and a half weeks of Kimura's absence from the Kamogawa gym, Aoki, Ippo, and Takamura went to the Kawahara gym to observe Kimura's spar against Miyata. After witnessing Kimura using an in-fighter's way of boxing, Aoki, Ippo, and Takamura discussed how impressive picking up a new fighting style in a short span of time is, however, Takamura believed that Kimura will soon realise something and have a desperate shock while trying to go through with his plan.
At Takamura's home, Takamura told Aoki and Ippo that Kimura has nothing and even if he comes up with an in-fighter strategy, it won't work as Mashiba is experienced in fighting in-fighters. Aoki and Ippo decide to tell Kimura this, however, they could not bring themselves to interrupt Kimura as they witnessed Kimura in a park practising by punching on a tire. After three hours of practising, Kimura leaves and then a group of people see the tire he was punching and began to mess with it until they were confronted by Aoki. The group became angry at the two for Aoki's threat if they don't stop messing with Kimura's tire and began attacking the two. Ippo told Aoki not to fight back as they are pro boxers. After they got beat up, Ippo embarrassed Aoki by noting how close he is to Kimura by stepping in to stop them. Aoki then expressed how thankful he is to Kimura as when they joined the gym, Kimura chose to take the harder path himself and be a junior lightweight, letting Aoki take the easy path of being on his own weight class in order to not get in each other's way. Aoki knew that when they train the same amount, Kimura suffered the most and that when he loses the pain is also worse, but Aoki agreed that winning must be better, especially a title match.
When Kimura had not come to the Kamogawa nor the Kawahara gym, Takamura believed that Kimura ran away cowardly asking Aoki and Ippo for proof that he didn't run away. Aoki and Ippo went back to Hara Park to see for themselves. There, they noticed that the tire is on the ground with marks on two different spots with one that was not there when they last checked. With the match poster up, Kimura returned to the Kamogawa gym and revealed that he has a new technique called the "Dragonfish Blow", he sparred with Aoki to show everyone at the gym. When Aoki missed an attack, Kimura stepped in and landed a left body blow on Aoki's block. Aoki was then knocked down by an unsuspecting right overhand while his attention was on Kimura's left.
When the day of Kimura's title match arrived, Aoki and everyone else went into Kimura's room, where Kimura informed everyone that if he loses, he would retire. Aoki told him that he got permission by Yagi to be his cornerman. When Aoki arrived to the ringside as Kimura's cornerman, Aoki got disturbed by Mashiba's eyes. When the match began, Aoki instructed to hit Mashiba first to take the pace. When Kimura had a dangerous fall in the ninth round, Shinoda attempted to throw the towel, however, he was stopped by Aoki, who pleaded to let Kimura end the match rather than a towel. Shinoda began to throw it again despite Aoki's argument but stopped when he witnessed Kimura, who, despite everyone predicting the opposite, was able to stand up again. The match then quickly ended when the referee noticed Kimura being unconscious while beginning to throw a punch, saving him from Mashiba's attack. With the match over ending with Kimura's lost, Aoki cried as he looked at Kimura and realises that he is still fighting in his head. While reporters were talking to Kimura, Aoki listened as Kimura told them that he has retired. At the Kamogawa gym, Aoki, like his other gym mates, were saddened by Kimura's retirement. When Wanpo went outside the gym and barked, Aoki and the others went outside and saw Kimura. Kimura then announced that he would come back by changing his given name from kanji to katakana.
After Ippo decided to help as a second for Kimura's upcoming match, he joins Aoki, Kimura, and Itagaki while doing roadwork. Aoki and Itagaki believe that since they are still active, it will probably be tough for Ippo to keep up with them. So they decide to leave Kimura to Ippo, so they can step on the gas. Except, they find out that Ippo is already in front of them again asking about how the coach is doing. Aoki mentions to Ippo that Kamogawa went to Nekota's place to get some rest, and they don't know when he will be back. They continue to discuss with Ippo about Kimura's opponent, while Ippo keep running back and forth between themselves.
Aoki later on attends Kimura's match. During Hayami's match before it, Itagaki asks Aoki about Hayami's current ranking, but he surprised to find out he isn't ranked. After he learns about Hayami's fight record, he is shocked that Hayami is still boxing. After Hayami loses his match, Aoki watches Ippo's antics as a second for Kimura's match. Kimura was able to win his match with Ippo's help. After the match, Takamura, Aoki and Itagaki goes karaoke as Ippo and Kimura head home. With Ippo as his second, Aoki has a match that ends with a KO after using the Frog Punch.
After saving Teru from some bullies, Ippo takes him to the Kamogawa Boxing Gym to try boxing. Aoki was impressed of Teru's drawing skill when Teru draws a picture to put on the sandbag, but ends up disappointed when he punches the sandbag. Later, Aoki and Tomiko stops by the Márquez. When they come up to the counter, Aoki asks if the reason why Miyata's last match was bad, was because of weight management or because of a certain someone's retirement, Miyata avoids the question. As Aoki leaves, he claims Miyata shouldn't wait any longer and move up to the next stage.
When Ippo visits the gym, he began mitt practising with Kamogawa. Outside, Aoki, along with the rest of the Kamogawa group watches. Aoki believes Ippo and Kamogawa were the perfect combo. Aoki is hopeful for Ippo to come back, but Kimura believes that if Ippo takes any hits, it would cause serious problems.
After Ippo is in shock for hitting Taihei, Umezawa carries him to the Chūka Soba. Aoki tries to comfort Ippo, suggesting to forget about the situation, as he didn't hit Taihei with a closed fist and only fainted. Ippo announces he will turn himself in, as he is a former Japanese champion who lashed out on a high school student. When Takamura, Itagaki, and Kimura arrive at the Chūka Soba, Aoki tells them that he left to turn himself in to the police. After hearing from Teru on how Taihei used to get into fights because of his older brother, Aoki and Takamura believe that Taihei's problems are his brother's fault. Teru worries about Ippo getting a criminal record, but Kimura states that Ippo's fists are full of justice and that whatever happens, nothing will change the bond that he and the gym members have with him.
At the gym, while talking about the situation with Ippo and Taihei, Takamura comes to a conclusion that the real villain is Taihei's older brother and prepares to show off his "Special 7-Years Killing: 100 Shots" that he will use on him. A bald Ippo comes into the gym and asks for Kamogawa in order to say his apologises.
When Taihei, along with Kintarō Kaneda, joins the gym under Ippo's training, Aoki notices Taihei. Kimura reveals to Ippo that Taihei is Aoki's little brother. After Aoki and Taihei is remembered from a TV show called "Heartwarming Special Presents: The Hectic Life of an 11-Person Family", Aoki and Taihei argue about their family's struggle when Aoki left them. Aoki tells Taihei how he never thought twice about helping him and the other siblings. Takamura, after finding out that Aoki is the older brother, uses the "Special 7-Years Killing: 100 Shots" on him as punishment for making Taihei get into fights.
Later, Aoki and Kimura attended Mashiba's OPBF title defence against Iga Shinobu. Aoki wished that Iga would lose in order for him to not get a world ranking. Aoki explained to Kimura that the reason Mashiba chose Iga, was because of Mashiba's black stars on his record, Kimura and Sawamura.
|29||Unknown||1?-?-3||1999-11||Unknown||Tokyo, Japan||?(8)||?||Main Card|
|28||WIN||18-7-3||1999-03||Unknown||Tokyo, Japan||7(8)||KO||Ippo was his second|
|27||WIN||17-7-3||1998-11||Unknown||Tokyo, Japan||8(8), 3:00||TKO||N/A|
|26||WIN||16-7-3||1998-06||Unknown||Tokyo, Japan||8(8), 3:00||TKO||Comeback Match|
|25||LOSS||15-7-3||1997-11||Iga Shinobu||Tokyo, Japan||7(8)||KO||Class-A Tournament Final|
|24||WIN||15-6-3||1997-09||Jackal Itō||Tokyo, Japan||10(10), 3:00||KO||Class-A Tournament First Round|
|23||LOSS||14-6-3||1997-04-15||Ponsa Kureck||Yokohama, Japan||10(10), 3:00||Decision||N/A|
|22||WIN||14-5-3||1996-09-12||Padawan Yoda||Tokyo, Japan||9(10)||KO|| "OPERATION WORLD DOMINATION"|
|21||DRAW||13-5-3||1996-03||Papaya Dachiu||Yokohama, Japan||10(10), 3:00||Decision||N/A|
|20||DRAW||13-5-2||1995-08||Papaya Dachiu||Yokohama, Japan||10(10), 3:00||Decision||N/A|
|19||DRAW||13-5-1||1995-04||Imae Katsutaka||Tokyo, Japan||10(10), 3:00||Decision|| Boxing Martial Arts|
Lightweight JBC Title Match
|18||WIN||13-5-0||1994-08-20||Paddy Magramo||Tokyo, Japan||10(10), 3||Decision||N/A|
|17||WIN||12-5-0||1994||Boy Allade||Tokyo, Japan||3(10)||TKO||N/A|
|16||WIN||11-5-0||1993-07-11||Snake Thomas||Tokyo, Japan||1(10)||KO||Come-Back Match|
|15||LOSS||10-5-0||1992-09||Jackal Itō||Tokyo, Japan||6(8), 1:18||KO||Class-A Tournament Semifinals|
|14||WIN||10-4-0||1992-07||Bull Ushida||Tokyo, Japan||6(6)||KO||Class-A Tournament|
|13||WIN||9-4-0||1992-04-20||Arman Garcia||Tokyo, Japan||7(10)||KO||"FLIGHT"|
|12||WIN||8-4-0||1991-9||Unknown||Tokyo, Japan||10(10)||KO||First Match Shown|
|?||LOSS||?-?-0||19??||Unknown||Tokyo, Japan||1(?), 0:30||KO||Loss against a South paw opponent|
|2/3||LOSS||1/2-1-0||198?||Unknown||Tokyo, Japan||?(4)||N/A||First loss between his 2nd and 3rd match|
|1||WIN||1-0-0||1988||Yamanaka Hiroshi||Tokyo, Japan||?(4)||KO||Debut Match|
Aoki has a tanned complexion with a body build that fits an orthodox lightweight in-fighter. He has curly dark brown hair in a short afro hair style with a prominent hairline. During his delinquent days, he had a more noticeable prominent hairline with shorter hair. He has dark brown eyes, large nose and pointed ears. In addition, Aoki has relatively short thick eyebrows and a wrinkle on his forehead.
After Aoki's draw against Papaya Dachiu, due to a promise, Takamura cut Aoki's hair into a broccoli-style.
During his youth, Aoki was known for his troubled school life as a delinquent. He, along with long-time friend Kimura, were known to participate in countless fights and brawls with 'rival' schools, with Aoki being the more aggressive and violent of the two. Throughout the series Aoki has shown a rather immature, mischievous and boastful personality, contrary to Kimura who is generally more laid back. Despite his often tough-looking demeanor, his overconfidence and goofy personality in and outside the ring usually earn him the frequent ridicule of other characters, and he is usually the butt of many of Takamura's pranks and attacks. Due to this, many characters, even to an extent Ippo, indirectly look down on and sympathize with Aoki and his embarrassing antics. However, he is mostly easygoing and is able to get along well with others, also usually being the one to help Ippo out with his girl-problems when around Mashiba Kumi. A long-running gag is that Aoki keeps revealing impressive talents, that sadly have no connection with boxing. His prankster personality extends to his own teammates and is most notably reflected in his attitude towards Ippo and (at times) Takamura. Together with Kimura, he is paired into the Aokimura duo by Itagaki Manabu.
Aoki's taste in women is seen as a running joke where, in contrast to the tastes of his gym mates, Aoki places his preferences in women considered 'ugly' by everyone else. Aoki admits that he gets nervous around beautiful women, specifically his ex-girlfriend Miyuki (who was caught cheating on Aoki with another guy), and is unable to make any further advances on them. However, surprisingly, Aoki seems to be very kind towards women and he himself prefers to judge them firsthand not by their looks, but as a person, unlike Kimura and Takamura. Even though he may have a taste for 'ugly' girls, he is able to hold a girlfriend, Tomiko, longer then any other members of the group.
Despite not being a terrible boxer overall, Aoki's boxing is largely downplayed in the series, making him pale in comparison to boxers like Takamura, Ippo, Itagaki and oftentimes, Kimura. His outlandish personality is usually reflected in his boxing matches where, due to his comparatively unexceptional boxing skills, he constantly thinks of odd techniques to deceive and confuse opponents. He uses unorthodox methods to ruin his opponents' rhythm; it was stated by Kimura that no one is better at ruining a boxer's rhythm than Aoki. He is also a decent out-boxer, and able to switch from orthodox to southpaw. Lacking any special skills to speak of, Aoki's matches tend to end up becoming extremely messy mud fights, much to the displeasure of his audiences. Eventually, his 'Frog Punch' became a trademark and earned him the nickname 'Leap Frog' or 'Frog Man' by his audiences. It is then mentioned by characters in the series that Aoki's boxing ability can be comparable to that of a national champion's.
Because of a previous right straight from Takamura that caused him to flinch every time he faced a right straight in the ring, Aoki's potential was held back a significant amount. This has made him easier to hit, making him lose patience and resulting in the many "mud fights" he's had throughout the years, but this was fixed by having him wear special headgear while having Takamura throw repeated right straights at him. Takamura also admits that Aoki's natural boxing ability can be greater of that of Kimura's should he overcome his weakness. Aoki also has a weak jaw.
- "Aoki" (青木) means the shrub, aucuba japonica. Furthermore, "ao" (青) means "blue" or "green", while "ki" (木) means "tree".
- "Masaru" (勝) means victory.
- On top of being a skilled boxer, Aoki is incredibly skilled in baseball, bowling and cooking. However, he does not know how to swim.
- Aoki is a fan of Roberto Durán, having a poster of him in his room, as well as mentioning him a couple of times throughout the story.
- This indirectly makes Aoki a fan of Takamura, as Takamura is based on Roberto Durán.
- In Round 151, Morikawa listed Aoki's fight record as 14 matches - 10 wins, 4 losses, 4 KO's prior to the semi-final match for the Class A Tournament. However, in the match poster for his title match with Katsutaka Imae, Morikawa listed Aoki's record as 16 matches - 10 wins, 6 losses, 6 KO's. Even though Aoki's fought in 4 matches since Round 151. Based on Round 151 record, Aoki's current record is 27 matches - 17 wins, 7 losses, 3 draws.