The character known as Leader heads the antagonistic Gyulassic Group (alternatively spelled Gulassic Group). Originally a developer at KOGC Co., Ltd., he designed video games including the title "X." He resigned after witnessing gamers violently reenact a fighting game in a KOGC Game Garden arcade and discovering KOGC processors were repurposed to power military missiles causing harm and fatalities. This misuse of gaming technology deeply distressed him.

During a physical attempt to intercept a missile attack, he sustained severe injuries from the explosion. Resurrected by *Game Center Arashi* protagonist Arashi Ishino, his mind was transferred into a mechanical or cybernetic form, leaving his body visibly scarred and bandaged. His physical design and ability to stop missiles barehanded pay homage to Sega's fictional mascot Segata Sanshiro.

As the Gyulassic Group's leader, he orchestrated world conquest by manipulating the Best of Arcade Gamer tournaments. He deployed subordinates Miss Alka and the Four Lords—Chizuru Jumonji, Melody Honey, a velociraptor named Raptor, and the entity Mister 20—to disrupt the tournaments. Mister 20 acted as his avatar in the game "X," serving as its bonus stage final boss.

A critical revelation exposes him as Fubuki Sakuragasaki's biological father. Confronted by the series protagonist, he reevaluates his goals, abandoning world conquest to journey across vast seas. He entrusts Fubuki's care to her mother Ruriko Sakuragasaki before departing.