Jashugan is the reigning champion and undefeated "Emperor" of the Top League in the brutal sport of motorball. His background before his career is largely unknown, but he began as a rookie in the highest league five years before the story's start, having lost both his parents and supporting his younger sister, Shumira, in the Scrapyard. In his rookie year, a deadly accident with his rival, Esdoc, caused him massive brain damage. He was saved by the eccentric genius Desty Nova, who performed a reconstructive surgery called Gehirn Umbao, using nanomachines to rebuild his cerebral cortex. This procedure gave him the abilities to become champion, but at a terrible cost: he suffers from increasing spasmatic attacks that cause his heart to flatline, leaving him in constant danger of death.

Jashugan presents a dual nature. On the surface, he is a confident and prideful athlete, a notorious player who is so skilled he often competes with a handicap, such as removing his own arm, just to give himself a challenge and test his abilities. He is feared and respected by fans and competitors alike. Beneath this exterior, he is a surprisingly caring individual, particularly towards his sister Shumira, whom he loves deeply and wishes to secure a stable life for. He is also deeply troubled by his own mortality. Despite his power, he is profoundly fearful of his "absolute death," a dread that holds him back from fully committing to his martial art, which requires one to become a machine and abandon the fear of death.

His primary motivation is to provide for his sister, asking his doctor, Daisuke Ido, to marry her to ensure her future. However, he is also driven by the pride of an undefeated champion and a desire for a worthy final opponent before his impending death. In the story, Jashugan serves as the ultimate rival and a mirror for the protagonist, Alita. They recognize a deep kinship in each other, seeing themselves not as hated enemies but as competitive equals who share the same lonely path as powerful outsiders. Jashugan is possibly the opponent Alita respects the most.

His most significant relationship is with Alita. Initially dismissive, he grows to respect her raw strength and sees her as a worthy successor to his reign, willing to fight against his own failing body just to have their final match. With Daisuke Ido, Jashugan has a relationship built on trust after Ido resuscitates him; he entrusts Ido with his sister's future, though he initially suspected the doctor of having ulterior motives. With his sister Shumira, he is loving but rarely expressive, and in a final act of self-determination, he sedates her to prevent her brainwaves from being used to save his life during his last race, ensuring he can fight without a safety net. His final rival is Ed, an old friend and competitor who vicariously seeks to surpass Jashugan by managing Alita.

Jashugan's development is a tragic arc about confronting death. Knowing his time is short, he organizes a championship race against Alita. He rejects his master's advice to kill his sister and become a perfect, heartless machine, instead choosing to fight for her sake and his own honor. During the final race, he suffers a fatal flatline just as he is about to defeat Alita. In an astonishing feat of will, he uses raw chi power to reanimate his clinically dead body, lands one final blow to defeat Alita, and then dies for good, his body melting away. His legacy endures, as Alita keeps a poster of him and later confronts a vision of him in a dream sequence, finally defeating him after he encourages her to surpass the heights he could not reach.

Jashugan possesses formidable abilities. He is the sole master of the cyborg martial art Maschine Klatsch, which his motorball body is customized to maximize. He is a master of chi control, allowing him to focus immense power into his attacks and even into a weak civilian body. His motorball body features powerful grinders built into his arms that can rotate at high speeds to tear through opponents. Notable techniques include Sidewinder (Mode 89B), an incredibly fast corkscrew punch; The Snapping Gator (Mode 47), a powerful throw; and Reflective Resonance, which creates destructive vibratory feedback by matching an opponent's chi. His dominance is such that he must race with handicaps, like removing his right arm, to make competitions fair. His greatest ability, however, is his sheer fighting spirit, which allowed him to temporarily defy death itself through sheer force of will.