Marito Jin possesses fair skin and a muscular build. His long lime-green and black hair typically styles in a half-up, half-down arrangement with a heart-shaped bun and framing bangs. Pink eyes mirror his sister Mahoro’s, accentuated by multiple piercings: lobe, helix, and snake bite varieties, plus a silver face chain stretching ear to ear. A lime-and-purple butterfly tattoo adorns his left shoulder, inscribed beneath with "The Folly of Enthusiasm." He favors bright clothing, often ombre white-to-yellow shirts with green accents, layered with neck chains—including a red-and-blue lightning bolt matching his gang—and bracelets on his left wrist. Eccentric and enthusiastic, Marito revels in food—especially Maji kebabs and seafood gratin macaroni—and combat, visibly exhilarated when opponents strike him. Despite this energy, he frequently naps lazily in the Siguma Squad clubhouse. He fiercely protects Mahoro, having fought or defeated at least 35 individuals like Arajin Tomoshibi to defend her, yet consistently distances himself, demanding she avoid gang activities and leave group settings. Marito met Outa in middle school, where they earned the "God Kings" moniker. By high school, burnout led him to reject major gangs like Minato Kai and Ikki Union. Witnessing Kenichiro defeat Ikki Union’s leader, Ransei Shiba, reignited his fighting spirit; he attacked Kenichiro with a flying kick but was ignored, leaving him baffled. After Outa became Ikki Union’s leader and lost to Kenichiro, Marito intervened, sparking an inconclusive fight that revitalized him. He renamed the gang "Siguma Squad" after lettering on his seafood gratin cup—though members misinterpreted it as "singlemindedness." Disrupting Mahoro’s date with Arajin, Marito fought him and grew impressed when Senya-merged Arajin knocked him backward. He persistently recruited Arajin into Siguma Squad, hosting a welcome party where Outa was assaulted. This escalated tensions with Minato Kai, prompting Marito to declare war. At the Colosseum, he battled Kenichiro one-on-one until a collapsing floor rendered both unconscious. Recovering, Mahoro tearfully hugged him, but he reiterated his demand for her departure. Hospitalized after Matakara Asamine—merged with Ichiya—inflicted severe injuries during a school-intercom challenge, Marito remained comatose for three days, awakening only when Mahoro mentioned Kenichiro’s name. Later, he attended a reconciliation party at Chu Chu Chinese Restaurant with both gangs. Relationships include a complex dynamic with Mahoro, balancing protectiveness with enforced distance; a longstanding partnership with Outa since their "God Kings" era; a rivalry with Kenichiro fueling his combat passion; and persistent recruitment of Arajin into Siguma Squad despite initial resistance.