Oni-san no Tokoro e Mairimashita

Sinopsis Oni-san no Tokoro e Mairimashita

A girl was given to an oni as a sacrifice, however, he had merely asked for a servant. Since the oni in question is against child labour and she has no place to go, he decides to make her his temporary "wife" in name. So the young girl and the cheerful oni begin their warm (married?) life together. (Source: Natalie, translated)