It's Kimetsu no Yaiba X Male Reader. Pretty straight forward. Male X Female.

Her life was trapped within her own darkness, but she had enough. She will see through her darkness to fight for the future. Ended : 25 January 2020. art by : Guweiz --- #1 in kimetsunoyaiba #1 in giyuutomioka #1 in kibutsujimuzan #1 in originalcharacter (😭) #1giyuutomioka