JakeTheBank
Return of the King
Never thought I'd be posting scans in favor of Batman, but I do feel pretty strongly that he wins the willpower contest here. Anyway:
Bruce's sense of will and identity is so potent, he manages to make up a "back-up" personality in case he's ever traumatized or otherwise not consciously able to defend his mind.
In order to fully appreciate his next willpower feat, here's an explanation of the creature known as "The Lump". Essentially, the plan is to make an army of Batmen, all armed with his psychological and physical prowess.
While inside the realm of Bruce's psyche, the Lump unleashes a potent psychic attack, forcing him to relive his greatest defeat in an instant.