During the first part of the Chapter 5 boss battle at the end of Mt. Gundor, while the boss runs at you and while Julia is one of your support characters, have Julia confuse the boss. The boss will glitch, and be stuck running in place, and will remain stuck until you use an attack that knocks him back. A noteworthy example of an attack lacking this knockback are the Machine Gun Arms on the Ridepod; using such attacks, you can quickly eliminate the boss's health without any risk to yourself.