Tatsumi Leonard Aragaki (アラガキ ) was Coach Nanbu 's former student and the 17th ranked boxer in Megalonia. He was drafted into a war ten years ago and lost both his legs from the knee down during an accident. He returned to the Megalo boxing ring after receiving prosthetic feet. When he returned from war, he eventually became a member of a gym that is frequented by veterans. Originally, his goal in Megalonia was to go as far as he could, but when Joe joins the tournament, his goal becomes to destroy Nanbu's newest creation.
Before Megalonia and before he was called to war from the reserves, he was a driven boxer training under Nanbu. Their relationship had been strong and Aragaki flourished under Nanbu's tutelage. He has a strong and hopeful attitude. Eventually, he is called to war and while he and Nanbu are concerned about what will happen while Aragaki is at war, both still have faith that they will see each other again.
After his injury, Aragaki changes. For his first year after returning home, he is haunted by his memories of the explosion and his terrible wounds. Like many veterans, he is ill with post traumatic stress and gets to such a fearfully low point that he considers suicide. When he is reminded of Nanbu, he loses the will to kill himself and goes off to find Nanbu. When he sees that Nanbu and his gym are gone without a trace, he loses himself again. The time between Megalonia and his return to his pit of depression is not totally elaborated on, but he eventually regains confidence when he gets his prosthetic legs.