Not too long ago, my computer crashed, and I lost my to-read list of manga. My fault, I should've backed it up.

I remember there was one on there where a demon was a raising/acting as a teacher to a young girl. They lived in a mansion, and the girl is not able leave. From what I remember, it's not a romance - the girl is like five or six, and the demon is more of a teacher figure to her. I seem to recall the demon's head is a skull, too - kind of like the Ancient Magus' Bride, but it's not the Ancient Magus' Bride that I'm looking for.

Does anyone know what I'm talking about?

Is it Totsukuni no Shoujo?

Your title also made me think of Hana to Akuma & Hanatsukihime but they don't sound like your description.

Totsukuni no Shoujo! That was it. Thank you ?