Reiren, an unfortunate girl sold to slavery by her own parents, was bought by Mr. Walter, a Necromancer who lost his daughter. He decided to adopt her as his daughter, and teach her about Necromancy.
Fate worked mysteriously, Reiren was able to see Leila, Mr.Walter's deceased daughter who even himself unable to see, and befriended her.
SSSC V, All three prompts - https://forum.scribblehub.com/threads/sssc-v.1035/
Cover from here: https://www.pixiv.net/en/artworks/76478180