Sera and the arch angels took Nikki eye out and injured her and banished her to hell after she try to convince sera sinners can be redeemed

Nikki sobbing in hell as she heard foot steps it was Lucifer with razzle and dazzle he took his jacket off and puts it on her shoulders

Lucifer: oh sweetie what did they do to you? As he saw her eye was taken out and her injuries

Lucifer picks her up and hugs her and decided to adopt her as his own as he got a wet cloth gently clean her wounds