Shu yo, Omukae no Jikan desu

Is my adorable little nephew the reincarnation of the demon king Lucifer!?

Chris, a picture book author, takes in his nephew after the loss of Chris's brother and sister-in-law due to an accident. Noah is a strange and eccentric child with the ability to communicate with animals. One morning, overwhelmed with his new parental situation, Noah darts out into the road?! However, the person who saved Noah before it was too late was Harvey-sensei, the nursery school teacher, a demon with black wings and horns!! Revealing his true identity, the demon kneels down saying, "I have come to take you back, Lucifer-sama," announcing that Noah is the reincarnation of the demon king!?

(Source: Tokuma Shoten, translated)