Shokei Flag no Akuyaku Kizoku ni Tensei Shita ga, Shinitakunai node Yami Mahou wo Kiwamete Heroine-tachi wo Sukuimasu

Waking up inside a video game, the protagonist finds he has become Diablo, the most reviled noble in the setting, whose story ends in an agonising revenge carried out by its own heroines. Instead of running, he decides to answer for the cruelty the original Diablo inflicted and protect the very women that version of him wronged. Surviving brutal trials and forcing himself well past his limits, he chases the power needed to rewrite the ending waiting for him.