Dealing with the Lords of the Divine Alliances was a little problematic. The Lords were Divine Lifeforms and several hundred years old. Some were even older and should have been knowledgeable and thus understanding of their situation. Unfortunately, Divine Lifeforms were also known for being prideful. In fact, even Higher Lifeforms, especially young Higher Lifeforms with above-average talent, were arrogant and unnecessarily prideful.
Crushing their pride might not be the best solution, but it was certainly the most time-efficient way to become their Lord. If crushing their pride didn't work, and they were to turn against him…they would have to die.
Michael didn't want to kill them as they worked together to defeat the Dragys, but he was not a pushover either. If they wished to fight him, Michael would jump into battle right away.