Fandom Otome/Chinese novel

Idea:  A demon king gets reincarnated into a normal world.

Infor: A woman gives birth to a reincarnated demon king from a fantastic world. The demon king had got hit by a spell from a spy sending him into reincarnation. The woman marry to a Japanese husband and have 3 kids with him. Her husband is a scientist. The demon king is the oldest child and have two younger siblings who are twins. The twins are a boy and girl. The demon king still have all his memoirs. He live in his reincarnated world for 15 years until his loyal subjects found him. He return back into his fantastic world with his family as they as while turn into demons just like him.