Gensou Shinkou

Gensou Shinkou summary:

A mysterious man named "Ryo" who has lost his memory wakes up in a different world populated by monster girls (fantasy species) that easily surpass the power of humans. He possesses a certain power, the skill of "charm", which forces him to increase the likability of all monster girls!
Despite his distress, Ryo uses his power to seduce all kinds of monster girls and build a harem. All in order to achieve a certain goal...!
Eros and carnage intersect in this otherworldly adventure tale that opens at!