Well, Rowena is often drawn to power, so I can see her seeking out Celeste if she gets wind of what she’s up to.

Unfortunately, Celeste disdains actual witches, as useful as she finds their powers. Though she might be interested to know Rowena is able to use magic without demon interference, she’s already met witches like that in the past. She won’t let Rowena come close to her plans, and Rowena would spurn this treatment.

Queue them becoming worst enemies and Rowena working to upset Celeste’s plans, especially if it helps her learn a few angelic secrets.