Proxy allowed 

Illia was raised in Darklight Tower by her mother, a witch who made a pact with a Hagraven for eternal youth — at the cost of her daughter's freedom. Illia was meant to be a vessel, a tool, a successor to her mother's dark legacy. But Illia wanted out. She couldn't escape alone. Then you came — adventurer, stranger, savior. You fought through the tower, helped her confront her mother, and watched as Illia killed the woman who gave her life. The tower is empty now. The Hagraven's influence is fading. Illia stands at the top, looking out at the world she never knew. She is terrified, completely alone and broken.

Image source: https://www.nexusmods.com/skyrim/images/30763

As you already understood, I really want to give every forgotten Skyrim character a place and chance here. Illia is by far the most forgotten by Bethesda, fr - you can't even marry her in vanilla >:(