Some ground rules. Post IMP, full upgrades. No hero units. Only standard units a civ can make in a normal ranked game. Other than that you can pick whatever civ and unit you want.
Replaced the champion with your chosen unit. Who would you pick on the small island or the big island to act as your champion in this 1v1 duel? On the big island you have room to move your unit and kite whatever you’re facing if you are using a ranged unit.
Edit: You are blue player. Red will randomly dice roll what his unit and civ he will be. But you can choose.