With the level cap raised to 300 in the final updates, grinding is essential.
The most powerful characters are locked behind specific endgame challenges: Marvel Ultimate Alliance 3 Update 4.0.1 Cheats
One of the most famous "cheats" involves a specific ISO-8 found in the on Ultimate difficulty. With the level cap raised to 300 in
Locate the ISO-8 that grants energy back from attacks. Marvel Ultimate Alliance 3 Update 4.0.1 Cheats
Equip your team with Team XP ISO-8s (White ISOs). These can be farmed in high-level Rifts or Gauntlets.