The SSS-Rank Goddess Chose Me

Killed in humanity's last stand, Steven wakes up fifteen years earlier. This time, he ditches the girl who betrayed him and saves Bianca, a bullied classmate destined to become humanity's strongest warrior. As she rises to SSS-rank, his B-rank powers hide a terrifying secret: the world-ending beast now lives inside him. Can he rewrite their fate, or is he becoming the apocalypse itself?