Welcome to Demon School! Iruma-kun

When Mafuyu Oribe and her adopted sister Tomo rescue a strange wounded man, they have no idea what they’re getting involved with or what the consequences will be. Alexander Nikolaevith Hell is an Iron Qwaser, one of many opposing factions of super-warriors.

Issei Hyodo is your average perverted high school student whose one wish in life is to have his own harem, but he's got to be one of the unluckiest guys around. He goes on his first date with a girl only to get brutally attacked and killed when it turns out the girl is really a vicious fallen angel. To top it all off, he's later reincarnated as a devil by his gorgeous senpai who tells him that she is also a devil and now his master! One thing's for sure, his peaceful days are over. In a battle between devils and angels, who will win?

Awakening from magical stasis after a thousand years, the Dark Lord Leonis suddenly finds himself in the body of a ten-year-old boy! He quickly meets Riselia, a girl confronting the Voids, creatures that have nearly exterminated humanity. Determined to uncover the mysteries of this strange new era, Leonis enrolls in Excalibur Academy, a school that trains students to fight back against these enigmatic monsters. Could the Voids hold some connection to Leonis's past?

In his past life, he was known as Demon Lord Varvatos, an all-powerful magic user and ruler. But he was lonely after the loss of his friends and loved ones during his rise to power, so in his dying moments, Varvatos cast a reincarnation spell so that he'd get a second chance at just being a normal guy. At first it looks like that's going to work – he's reborn thousands of years later as villager Ard. Unfortunately for him, his memories are still intact and he's not aware just how much has been lost over the time he spent not existing, and it looks like that's going to cost him his normal life.