Ren'ai Harem Game Shuuryou no aga kuru Koro ni

Ren'ai Harem Game Shuuryou no aga kuru Koro ni summary:

Kohinata Asunaro is your ordinary perverted high-school student who likes light novels and romance games. He has no interest in having a "3D" girlfriend and is content just fantasizing on the pretty girls of his school to create his own imaginary harem. But one day he accidentally releases Zepfur, a demon who promises to make his fantasies a reality.

The day after, one of those girls, Furuwada Serika, is summoned by Zepfur and explained the rules of a game: the girls of Asunaro's "harem" must earn points by competing for his affection. The winner will be the one whom Asunaro chooses as his sole girlfriend… and the losers will experience an infinite loop of horrible deaths in Hell. For Asunaro, it's just a romcom fantasy coming true. For Serika and the others, it's a battle for survival. Published in Monthly Shonen Sirius.