Raise wa Kimi no Mono

A young girl makes a promise with the God of Indignation, in exchange, she offers her soul. Appearing in front of a misfortunate girl is that very same God. He has come to fulfil his promise to her in a past life and offers her a single wish... In exchange for her soul, of course. [aoc.moe]

Teenage girl who is living under strained family circumstances as her father is absent and her step-mother only cares about her own son. Her stepbrother who is a talented dancer has an accident and is hospitalized with the doctors thinking he wont be able to walk again. Upset about this as she cares for him the girl sees a strange figure in his room and soon after a strange man appears before her claiming to be a God of Resentment. He reveals that in a past life he promised her something in exchange for her soul in her next life. If she upholds their bargain he will make it so her step-brother is healed. She agrees.

Original Web Manga