Bite My Sister

After becoming a Vampire Progenitor, the first thing Pantre did was bite his little sister.

Having inherited the Blood God's ruined world, Pantre changed class to Vampire Progenitor and set off on a journey to collect the world-suppressing divine artifacts (his little sister) and use them to hold the world together, while occasionally taking on little tasks in other worlds (collecting little sisters).

P.S. This book is toxic.