To Save the World, Can You Wake Up the Morning After with a Demi-Human?

Humans and demihumans live together in peace, and in this world, there's a normal human named Hironori Tabata. One day, an angel named Suzuki Lina went out to find him and said she wants to have sex with him…the reason—? The Demon King will be resurrected in the future and Tabata's son will be the hero that will fight and defeat him.