Characters
Joe (ジョー, Jō) / Junk Dog (ジャンクドッグ, Janku Doggu)
Voiced by: Yoshimasa Hosoya (Japanese); Kaiji Tang (English)
Junk Dog is an underground Megaloboxer from the outskirts of town whose real name is unknown. He is forced to throw fights to earn money for his crooked manager. He initially fights with old Gear that is constantly in need of repair. He takes on the name "Joe" when he has a Citizen ID forged in order to enter the Megalonia tournament. He later takes on the ring name "Gearless" Joe (ギアレスジョー, Giaresu Jō) as part of a gimmick to rise in the rankings quickly, fighting without Gear against Gear-equipped opponents.
In the second season he takes on the moniker "Nomad" (ノマド, Nomado), drifting to different underground fighting rings with simple Gear and fighting opponents to fund his painkiller addiction. It is mentioned in the background that sometime after vacating his Megalonia belt, he lost an exhibition match to Yuri's disciple and the next champion, Edison Liu, and has not been seen in a pro Megaloboxing match since. After meeting Chief, Joe decides to be his cornerman while Chief and Marla help him fight his painkiller addiction. He later returns to his hometown to make amends to his former friends, who had almost seven years prior cast him out for abandoning them as Nanbu died to fight in a boxing match.
Gansaku Nanbu (南部贋作, Nanbu Gansaku)
Voiced by: Shirō Saitō (Japanese); Jason Marnocha (English)
Nanbu is Junk Dog's manager, coach and a gambler with a drinking problem who keeps making him throw fights, even though deep down he believes in Junk Dog's abilities.
Between the first and second seasons, Nanbu dies of cancer. Sachio and the other children the two befriended hold resentment towards Joe for "abandoning" Nanbu as he was dying.
Yuri (勇利, Yūri)
Voiced by: Hiroki Yasumoto (Japanese); Lex Lang (English)
Yuri is Yukiko's bodyguard and the Megaloboxing champion. He seeks out Junk Dog after the latter insults his owner, meeting him in the underground ring he easily defeats him before telling him to work his way up in Megalonia if he wants to fight him again. Yuri is equipped with a unique prototype "integrated" Gear, which is surgically grafted directly to his arms.
In the second season, Yuri has become Edison Liu's boxing coach.
Sachio (サチオ, Sachio)
Voiced by: Michiyo Murase (Japanese); Erica Mendez, Clifford Chapin (Older; Season 2) (English)
Sachio is a young orphan boy from the impoverished Restricted Area who is talented with using and fixing machinery, which he and his friends often use to steal goods that they exchange for "Red Candy", a type of drug.
In the second season, Sachio, now a teenager, has become an underground Megaloboxer. He is noted to not have the resolve or natural talent for Megaloboxing, often badly losing matches, and holds Joe in deep contempt for his actions as Nanbu was dying.
Yukiko Shirato (白都ゆき子, Shirato Yukiko)
Voiced by: Nanako Mori (Japanese); Erika Harlacher (English)
Yukiko Shirato is the head of the Shirato Group who oversees the Megalonia tournament.
Fujimaki (藤巻, Fujimaki)
Voiced by: Hiroyuki Kinoshita (Japanese); Jamieson Price (English)
Fujimaki is a mob boss who sets up fixed fights for Junk Dog and Nanbu. He assists the duo in acquiring a forged Citizen ID so they can enter Megalonia and pay him back with the prize money after Junk Dog refuses to throw a fight.
Tatsumi Leonard Aragaki (タツミ・レナード・アラガキ, Tatsumi Renādo Aragaki)
Voiced by: Makoto Tamura (Japanese); Greg Chun (English)
Aragaki is Nanbu's former student. He was called up for military service a few years before the start of the story. During his time as a soldier he was directly hit by an explosion which cost him his legs and burned half his face off. When he returned home he started to suffer from PTSD which led him to attempt suicide and he also felt abandoned by Nanbu after finding that he had closed down his gym when he thought Aragaki had died. He makes his return to Megaloboxing 3 years before the start of the story and fights his way up to rank 17, when he hears that Nanbu has a new popular Megaloboxer named Joe he vows to destroy him so that Nanbu can feel his pain, but he also wants to earn money from sponsors so that he can repay everyone from the veteran's association for giving him his life back.
Miyagi (ミヤギ, Miyagi)
Voiced by: Yōhei Tadano (Japanese); Jake Eberle (English)
Mikio Shirato (白都樹生, Shirato Mikio)
Voiced by: Tatsuhisa Suzuki (Japanese); Robbie Daymond (English)
Mikio Shirato is Yukiko's older brother and the developer of Ace, a state-of-the-art Gear equipped with artificial intelligence that allows it to read and predict an opponent's moves, formulating the perfect counters and strategies. Mikio is arrogant, egotistical, and smug, believing "stray dogs" like Joe are not worthy of standing in the same ring as himself. Mikio was passed over for becoming the head of the Shirato Group in favor of his sister, a fact that causes him to hold a grudge against her.
In the second season, Mikio has become a professor at a local university.
Mac "The Hero" Rosario (マック, Makku)
Voiced by: Atsushi Miyauchi (Japanese); Christopher Wehkamp (English)
An Uruguay Megaloboxer sponsored by the technology company ROSCO. Formerly known for his explosive temper and aggressive moves in the ring, he retires from the sport after watching Joe and Yuri's bout at Megalonia. He later joins the police force and is seriously injured during a shootout, causing full-body paralysis. He is eventually approached by ROSCO CEO Ryugo Sakuma and agrees to have an experimental brain chip and integrated Gear system known as BES implanted, which allows him to move again and inspires him to rejoin the Megaloboxing world to showcase the BES system's capabilities. When he reaches excessive stress levels, the implanted brain chip causes him to enter "Mac Time," a mental state where he becomes hyper-focused. Coming down from Mac Time temporarily regresses his mind to a childlike state, with episodes getting worse over time.
Ryugo Sakuma (佐久間, Sakuma)
Voiced by: Chikahiro Kobayashi (Japanese); Tyler Walker (English)
The CEO of ROSCO, an eccentric young genius who developed BES.
Ignacio "Chief" Martinez (チーフ, Chīfu)
Voiced by: Miou Tanaka (Japanese); Chris Guerrero (English)
An undocumented Uruguayan Afro-Latino immigrant and the unofficial leader of his community who pretends to be a former ranked Megaloboxer to earn money in underground boxing matches. He was inspired by Joe to immigrate and plans to win Megalonia to help secure a more permanent home for his people.
Marla (マーラ, Mara)
Voiced by: Farahnaz Nikray (Japanese); Jalitza Delgado (English)
An undocumented Afro-Latino immigrant who runs an auto shop within the immigrant community, trying to make an honest living.
Mio (ミオ, Mio)
Voiced by: Yumi Hino (Japanese); Kevin Thelwell (English)
Marla's son who often commits petty crimes in hopes of appeasing his friends from outside the community.
Edison Liu (リュウ, Ryū)
Voiced by: Masaya Fukunishi (Japanese); Aaron Roberts (English)
The current Megaloboxing world champion and Yuri's star pupil. He defeated Joe in a title fight one year after the first Megalonia, which ended up being Joe's final match before he left town and became Nomad.
Santa (サンタ, Santa) , Oichio (おいちお, Oichio) and Bonjiri (ボンジリ, Bonjiri)
Santa Voiced by: Momoko Taneichi, Noriaki Kanze (Japanese); Morgan Berry, Jessie James Grelle (Older; Season 2) (English)
Oichio Voiced by: Ami Naitō, Mitsuho Kanbe (Japanese); Michelle Ruff (English)
Bonjiri Voiced by: Reimi, Fukushi Ochiai (Japanese); Laila Berzins, Dallas Reid (Older; Season 2) (English)
Sachio's orphaned street kid friends from the slums of the Restricted area, who have become huge fans of Joe and the Megaloboxing fights, including the ones held in Megalonia.