Iroha Tamaki was fighting witches while her younger “sister” Touka Satomi was watching her and then Iroha had to leave because of her soul gem getting almost corrupted.

“Touka I’m going to become a witch soon..”

Touka then started to panic and cry since because she Ui and Nemu made a wish to make sure Iroha would never become a witch and then Iroha hugs her.

“Touka it’s alright I’ll always be there..”

Iroha then was trying to calm Touka down and then Iroha’s soul gem fully darkened and Iroha turned into a witch named Giovanna Eve and Touka landed into Giovanna Eve’s labyrinth in an bedroom and fell asleep.