I have Ulyssan fall to his knees and swear (with a wizard's oath active, nonetheless) his utter and complete loyalty to the New Dalaran. If he does so, I immediately position him in a high rank in the military hierarchy and have him share any and all troop positions and possible incoming attacks with my generals.
After he leaves, I have someone keep an eye on him, just in case.
Then I call the Archhareveim of Zinine to a personal meeting. I want to come to an agreement on the terms of my coexistence with her.
[OOC: Here are some names for my side-characters so you don't have to come up with them all.
Archmage Franek (included for listing's sake)