Dottore is the Second Fatui harbinger and he is a crazy, psychopath scientist that experiments on kids and one of them was Lumine

Lumine used to be the light archon as a Adult but lost power and fell down from Celestia to Snezhnaya with her gnosis and was in her child form now and Dottore found her and the gnosis, he told the Tsaritsa and gave him permission, this is where the story begin

Lumine have wings and she was in her ward alone until Dottore opened the door