Shuichi Iguchi, alias Spinner, possesses a reptilian mutation quirk manifesting as green scales, a lizard-like face, and purple-pink hair. Initially offering only wall-crawling with limited combat utility, his quirk's appearance fueled discrimination, leading to isolation and deep immersion in video games. Stain's ideology and televised final stand ignited a sense of purpose he previously lacked. Adopting Stain's attire, bandaged mask, and composite sword, he joined the League of Villains, convinced they shared Stain's goal to purge corrupt hero society. During the Forest Training Camp attack, Spinner clashed with pro hero Mandalay but proved easily distracted by compliments. He notably redirected Magne from killing Izuku Midoriya, citing Stain's recognition of Midoriya as a "true hero," prioritizing Stain's principles over League objectives. Though Midoriya shattered his sword and Mandalay captured him, Kurogiri secured his escape. Internal League challenges later prompted Spinner to question Tomura Shigaraki's leadership, especially after the Shie Hassaikai raid when a police convoy assault seemed detached from Stain's ideals. His frustration peaked during the Meta Liberation Army Arc as stagnant hideout life echoed his pre-Stain emptiness. Witnessing Shigaraki's resolve against Gigantomachia and Deika City's destruction shifted his loyalty from Stain to Shigaraki; he related to Shigaraki's hollow past and embraced his new vision. Promoted to lieutenant in the Paranormal Liberation Front, Spinner guarded Shigaraki during his transformation. Exploiting this loyalty, All For One granted him the "Body Bulk" and "Scalemail" quirks, drastically enhancing his size, strength, durability, and agility for the Final War. These quirks degraded his mental state, inducing feral behavior and instability. Reluctantly becoming a heteromorph symbol, he commanded 15,000 followers but failed to retain their loyalty after his Quirk-induced rampage caused excessive destruction. His resolve focused solely on aiding Shigaraki, culminating in a physical transformation during the Central Hospital assault. Following Shigaraki's defeat, Spinner confronted Izuku Midoriya, blaming him for Shigaraki's death and declaring Shigaraki his "first friend" and hero. After Midoriya relayed Shigaraki's final message, Spinner channeled his grief into writing a book to preserve the League of Villains' legacy. Scarred from Quirk overuse and hospitalized, he encouraged Midoriya to support heteromorph hero Mezo Shoji.