It's much simpler than that.
D'Hara wants to keep a balance of powers. Without LV, D'Hara is all alone in that part of the world.
Exactly, since LN already offered LV peace once we see it as them wanting to get one realm out of the war so they beat whoever stays then afterwards they kill the remaining realm. Maybe that wouldn't happen but do you really think we are going to trust the aggressive plotting lurians of LN, especially when we have evidence against them?
