Shu Ogata, a demon slayer standing 179-180 cm tall with messy black hair and gray eyes, founded the micro private military company I&S Office in Bayron City. Specializing in demon extermination contracts, he previously worked for the major PMC AAA Defender Co. before departing two years prior. He typically wears a black shirt under a dark green coat, full pants, and brown shoes. Born on September 2, he is over 20 years old with blood type O. Financially strained due to selectively underbidding on contracts, Shu prioritizes jobs aligning with his investigation into his family's tragedy. Twelve years ago, his father Isamu Ogata—a demon-hazard risk consultant—and mother Sayuri perished in a demon-related mining accident authorities blamed on Isamu. Orphaned and adopted by private military officer Miles Morgan, Shu received demon-slaying training from Akino Yugiri, his father's former apprentice, before joining her company AAA Defender Co. Three years before founding I&S Office, Shu entered a romantic relationship with Akino's daughter Ayano Yugiri, cohabitating until recurring dreams of his younger sister Kanna shifted his focus. Convinced Kanna survived the mine incident, he sought power to rescue her. This led to a contract with the centuries-old demon Kisara two years later, sacrificing memories to fuel her abilities. He subsequently left AAA Defender, ended his relationship with Ayano, and established I&S Office with Kisara as his sole partner. Memory sacrifices created surface-level traits resembling incompetence: reliance on Kisara for cooking, cleaning, and bills, and dependence on Ayano for financial bailouts. This strategy conserved potent memories to amplify Kisara's power. His combat proficiency remained intact, demonstrated through precise sniper shots and effective hand-to-hand skills. Mission successes slightly improved his finances, enabling occasional personal expenses like dining out. Relationships reflected fragmented memories. Aware of Kisara's romantic feelings, he treated their kisses as power-transfer rituals—later revealed as a method to preserve his memories within her while she consumed her own pre-contract recollections. He retained lingering affection for Ayano despite sacrificing relationship memories, maintaining cordial ties and operational collaboration. His history with ex-lover Sharon Holygrail involved betraying her during a demon-capture mission, causing mutual distrust; he eventually forgot her entirely. Miles Morgan, his foster father, served as a trusted informant until Shu discovered Miles's demonic pact with Asmodeus—forged to save his dying daughter. This pact led Miles to protect young Shu during the mine explosion, though Isamu triggered the blast to thwart Asmodeus. Forced to kill Miles in a confrontation, Shu grappled with the loss. His investigation confirmed Kanna survived, possessed by Asmodeus. After freeing her, she briefly fought Shu's allies before joining his household. Near the story's conclusion, Kisara annulled their contract without consent, returning all Shu's lost memories while sacrificing her own. This revealed she had preserved his memories and burned hers to power her abilities. Shu regained full recollection of his past, including relationships and motivations, while Kisara lost her identity and memories.