All of Ikkuiku's Novels
Monster Musume Harem wo Tsukurou!
On his usual way to home Mikado Tsuchio fell into a hole that suddenly opened on the ground. Just like that, Tsuchio falls in a different world, he lands on a Grappler Wyvern and manages to tame it. Tsuchio decides just like that to live in the other world, the reason for his quick decision: he wants to make a monster girl harem.