Misumi Shunu

At the age of 200, he was supposed to accomplish one final great feat and bring his long life to an end… or so he thought. But when he opened his eyes, he had become a baby!Thus begins his second life as Cross Elphid. Unlike his lonely previous existence, he now resolves to live differently—saving the weak and supporting one another through the bonds he forms with many people.A princess who is the strongest of knights, a beautiful young alchemist from a prestigious potion-making family, even a female hero who wields the power of lightning…While spending sweet, heart-fluttering days with these girls, he fully utilizes the 200 years of experience from his past life—and once again dominates the world with his cheat-level abilities!?

Aldnoah, the Demon King, takes his own life in front of the heroes and is reborn in the world a thousand years later. In order to see if humans have become strong enough to stand up to the Demon King, Aldnoah, who has grown into a young man, decides to attend the Academy for Heroes...