Final Fantasy Dimensions - Final Boss Chaos Elgo

Final Fantasy Dimensions (Android) This is the second time i beat it after grinding job, super bosses and getting fusion abilities. I've done the every optional bosses include Gladiator Hall Trio: Omega Weapon, Gigantuar & Adamantoise. But never clear them on max level. Omega still lv 5 and always wipe out my team with Omega Break, Gigantuar already max level but always beaten up with Knockdown. Adamantoise also max level but still can't manage to defeat it. I guess i have to move on to FF Dimensions II or another game already.