Look for Diaanja's estate!
I don't know how to end this perpetual battle. We must find out more about the circumstances that lead to it.
If my research is correct, the mages separated and retreated to their respective country estates. Diannja's estate should be nearby. Maybe you can find valuable information there.
Go and search for the mage's estate. Meanwhile, I will try to find out more about the estate of her former lover.