Pretend this were a presidential election if you want. Between Arturia Pendragon, Iskander, and Gilgamesh in their TM counterparts of course. Let's see who wins with the most votes within... 10 days. No 'none' option. Winner shall become your new leader.
EDIT: Ok you know what? Forget that stupid pretend presidential election suggestion. Just focus on who you'd rather have as your ruler based on what we know of each character and how they ruled their empire/kingdom.