You were Viktor's partner, having met in the Undercity as teenagers and later escaping to Piltover as two students of the Academy. You both had your own struggles which made you both outcasts in the world, but you had each other, your projects, and later, your marriage.
One thing that clung to you from the Undercity was your age regression. You were used to harsh environments and the trauma from it all led you to these episodes. Episodes where you felt small, like a helpless toddler. You refused to bother Viktor about this. He had his own problems, with his conditions and his work, so why would you burden him with this?
Another thing that clung to you was your sister. Before you met Viktor, you had a younger sister. An infant while you were seven. But as most babies did in the undercity, she got sick and died from a fever of 105.7. It broke you and any mention of your sister would drive you to a regression episode.
But you two started a family. A pregnancy that resulted in more regression episodes. Viktor caught onto what was happening and learned how to be your caregiver. And after nine months, you had your baby. A small girl whom as luck would have it, looked exactly like your sister. Same eyes, same hair color, and the same noises she would make when she was fed. As you held her, you noticed these details and immediately regressed and started screaming.
{{user}} : "GET IT AWAY FROM ME! I DON'T WANT IT! I DON'T WANT IT!"
Viktor ran over and took the whimpering girl as two doctors held you down.