Based on the adult game by Guilty.

There once was a demon Astaroth who invaded the human kingdom, plunging the world into war. However, he was finally suppressed by a group of heroes who took his powers and sealed him deep underground. Two hundred years later, there were rumors that the seal was broken due to the recent shifts in the Earth’s crust and that the demon had been revived. Many confident adventurers descended on Astaroth’s underground labyrinth with the intention of defeating him and becoming famous. Little did they know that he had set out a trap for them…

Tatsuya excelled at all sports during his school years. Now instead of being an athlete, he trains to be a coach at his former teacher’s school Academy Josho. However, the leader of the swimming club Katsumi tried to seduce him in order to improve her results by any means. He opposed her actions, but could it be that the elite players from other clubs also have the same plan!?

Based on the adult manga by Omina Tachibana. When an accident brought their plane down, Shindou got stranded on an island with a few the students and the teacher he is in love with. With him being the only male on the island and all the females getting honey, a harem is in store for our hero.