itch.io

I'm sorry for taking longer to reply! I lost access to my account for a bit. 'Corrupting' Rilliane is an 'Easter egg' more than anything. You need to obtain the "Necromancer's staff" and force her to wear that. Note that doing so will harm your relationship with her. But she will subsequently be less affected by further relationship losses. She will only remain in that state as long as she has the staff equipped. (It can later be upgraded)