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.
|29||WIN||19-7-3||1999-11||Unknown||Tokyo, Japan||7(8)||KO||Main Event|
|26||WIN||16-7-3||1998-06||Unknown||Tokyo, Japan||8(8)||TKO||Come-Back 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"|
JBC Lightweight Title Match
|18||WIN||13-5-0||1994-08-20||Paddy Magramo||Tokyo, Japan||10(10), 3:00||Decision||"PROOF OF POWER"|
|17||WIN||12-5-0||1993-08-30||Boy Allade||Tokyo, Japan||3(10)||TKO||"SOMETHING WILL HAPPEN!?"|
|16||WIN||11-5-0||1993-07-11||Snake Thomas||Tokyo, Japan||1(10)||KO||"THE ROAD BACK"|
|15||LOSS||10-5-0||1992-09||Jackal Itō||Tokyo, Japan||6(8), 1:18||KO||Class-A Tournament Semi-Finals Match|
|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||19XX||Unknown||Tokyo, Japan||1(?), 0:30||KO||Loss against a South paw opponent|
|2/3||LOSS||1/2-1-0||198X||Unknown||Tokyo, Japan||?(4)||N/A||First loss on his 2nd or 3rd match|
|1||WIN||1-0-0||1988||Yamanaka Hiroshi||Tokyo, Japan||?(4)||KO||Pro 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.
- In Round 948, Aoki's baseball stats was listed, where Aoki has a ERA (Earned Run Average) of 0.70 and a batting average of 0.857.
- It should be noted that any ERA under 1.00 is rarely seen in baseball. Usually only pitcher with a low number of innings pitched, or a relief pitcher having a great year. Only 3 pitchers have been under a 1.00 for their careers, where all were at the turn of the century in the 1900's.
- Normally a batting average higher than .400 is nearly impossible usually only with players with a limited at bats. Ted Williams was the last player to post a .400 batting average in a season in 1941.
- 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.