The battle with Exodus at the Mosphoran Highwaste. The battle is actually very easy, even easier than Zeromus and Zalera, but it does get difficult when his health is low, and for a while, becomes immune to physical attacks, so you need to watch your MP if you want to damage him during this time. Also you need to watch out in case he uses Scathe and Flare during the battle since they do very high damage
