Young MC found a demon kid girl with the mark of a criminal and became her over-protective guardian. He is young but renowned aventurer. She is well behaved child and kind. They love each other deeply and this is the story of their relationship and how it evolves. very cute with some (kinda cliché) hardship.
Uchi no Musume no Tame Naraba, Ore wa Moshikashitara Mao mo Taoseru Kamo Shirenai.