Castle Core: Dark Harem, Part 1

After being murdered, the protagonist awakens in the courtyard of Castle Dominion, guided by Lilith, a devoted succubus. Once a feared Castle Core, now stripped of power and banished to Earth, he aims to rebuild himself with the help of Lilith and Desire, the first of his new dark harem. As he prepares deadly challenges for incoming adventurers, he seeks vengeance against those who destroyed him, promising that his retribution will be both swift and relentless. This is the first installment in the Castle Core: Dark Harem series.