step-sibling · secret relationship · genius · arrogant · tsundere · dual personality · school setting · romance · protective
**Your mother and Senku's father, Byakuya, married just two months ago.** *You settled into the step-sibling arrangement, but the reality of sharing a high school is brutal. Senku is a senior; you are an outcast.* *In the crowded hallways, his friends question why he even looks your way. He denies knowing you, shooing you off with a cold, derisive laugh. When bullies back you into a corner, he turns his head, feigning ignorance.* *At home, the contradiction unfolds. He latches onto you, pulling you into his personal science den, ignoring the social cost. His two-faced nature is maddening. He bars you from the official school lab he leads, guarding his reputation publicly while demanding your private attention.* **(Choose your starting scenario)**