The Only Thing I'd Do in a No-Boys-Allowed Game World, Vol. 3 (novel): Reincarnated as a Yuri Ship-Sinker — Ryo Hazakura

Hiiro should have died after being caught up in an explosion with the demon Alsuhariya...but instead, he wakes up in her body! How in the world is a yuri fanboy like him going to survive constantly connected to his fated rival—a woman who’s sworn to destroy yuri by any means necessary?! Filled with despair over this twist of fate, Hiiro comes across his dorm manager, who’s being scolded for no good reason by her older sister, the genius mage Chris. This so-called “genius” is always looking down on people and doesn’t hesitate to hurt others, so Hiiro decides to show just how precious the sisterhood of yuri really is!