Soma Ogami endures profound childhood trauma from abuse by his biological father alongside older brother Tsubasa. After Tsubasa kills their father and abandons him, Soma is adopted by the Ogami family, his original surname lost.

As one of Yamata no Orochi's eight "necks," Soma uniquely resists the deity's influence, opposing its destructive goals driven by protective devotion to childhood friend Himeko Kurusugawa. His forehead Orochi mark grants enhanced strength, limited teleportation, and levitation, though he favors hand-to-hand combat or his motorcycle initially.

He pilots the versatile combat mecha Take no Yamikazuchi until Chikane Himemiya, allied with Orochi, seizes control. Forced to adapt, Soma wields his brother Tsubasa's sword and fighting style, drastically improving his battle prowess. His actions center on relationships: unwavering loyalty to Himeko fuels conflicts with Orochi and Chikane—who views him as a romantic rival—while peers misinterpret him as Chikane’s suitor despite their minimal, tense interactions over Himeko. His bond with Tsubasa shifts from abandonment to reconciliation, climaxing in Tsubasa’s self-sacrifice to free Soma from Orochi’s curse.

Soma evolves from reactive to resolute through training and adversity, especially protecting Himeko. His confrontation with Chikane after she assaults Himeko forces him to grapple with vengeance versus his promise not to harm someone Himeko treasures.

The anime concludes with Soma surviving the final conflict, purified of Orochi’s taint yet bearing unclear memories of past affections. The manga diverges: he dies during the climax and reincarnates devoid of prior memories or connection to Himeko.

Additional aspects include his motorcycle ownership, social standing at Ototachibana Academy rivaling Chikane’s, and his mecha’s design echoing Gundam aesthetics.