Onimai: I'm Now Your Sister! (Uncensored)

Mahiro Oyama, a self-proclaimed home security guard, lives a reclusive life in his room, spending most of his time playing erotic visual novels. His sister Mihari is concerned about his well-being and devises a plan to help him return to a normal life. She creates a medicine that alters his biological sex to female, leaving Mahiro with no choice but to live as a girl until the effect wears off.