He wouldn't be the main conspirator, nor be aware of the ploys anyway. All his capable retainers would make sure he reaches the top one smile at a time.
iirc Mireille already told him he should just unite the whole continent and all of his retainers were in agreement that he can/should go for it.
and even if Kran will become the emperor because Ars isn't suited for sitting on the throne, Ars's achievements along the way will be so great that Ars will have the option to demand favors from Kran (which of course he won't because Ars is Ars)