Should I just start executing the Khuzits?

I am the leader of the battanians and right now it’s us and the Khuzits (there’s maybe three Sturgian castles left) and right now we are playing tug of war over the same 5 castles and cities.

We have nearly 15k more men and have about 18 clans under my banner. Should I start executing the enemy to weaken them or will my clan betray me/leave? What is rhe worst that can happen

This is my furthest through yet in sandbox

Note I’m not playing any mods