18+ Isekai de Inmashi Harem

Ichirou, an ordinary otaku working adult, is summoned to another world. Unusually for an "outsider," he is a "powerless person" with no special abilities. However, he has "awakened" to the other world as the possessor of "incubus powers," which allow him to control women through his semen. Realizing this, Ichirou uses his incubus powers to seducing beautiful women and girls one after another, eventually rising to become the king of a country...!?

(Source: Kadokawa, translated)