High Level Spell Suggestion: Geis
Just a suggestion on a Sunday Morning: The spell Geis (geas): Cast on an opponent Channeler, forces the subject to accept any diplomacy deal offered that turn. Huge mana cost. After the spell wears off next turn, the subject has a -50% diplomacy shift towards the caster. This spell fails if the target is currently at war with you, or will not speak to you (due to low diplomacy rating).