that works for me! i think at the beginning, especially if i go the cassandra "nobody believes my prophecies" route, he will have been really hesitant to tap into his magic because he'd be afraid it would wreak havoc instead of help people, so she could have sort of helped ease him into it. he could have even gone a little power hungry at first once he got a taste of that power and is now trying to atone for the mistakes he made, which could have been what led to their paths diverging before coming back together