"It looks like the staff can be used to channel the user's power." So that magic Rita saw before was technically Yuya's. It resembles him, in a way.

"Those lines you can trace with it have a basic warding effect. You could probably enhance the effect by drawing magic circles or symbols..." If he knew any, which he probably doesn't. "It can also focus and amplify the effects of defense spells. You said you were practicing one with Strange before, right?" That could be a good place to start.