I think you are required to get her a seal.
Aspect of the Bear is the final skill on the Crusader - Berzerker skill tree.
So you managed to challenge the dominas with Best Girl in tow?
There are exclusive scenes if you offer them a soul shard. The scenes you get when you become their slave are different from the scenes you get after losing. Some of them also offer a multi domina pegging/ butt worship scene after you lose by clicking on the candle stick that will appear.
And this game isn't trash, only Worst Girl is.