Y'know I heard Demi is a pretty cool spell. It does, like, 1/4 of the enemy's HP. Heard it's pretty useful against enemies that have many tens of thousands of HP.
Just when I couldn't believe your luck against the Great Malboro, you go ahead and take a full-force Meteor from a King Behemoth. Great job, MATT.
In all seriousness, Meteor is actually a physical attack so Magic Break wouldn't do jack, and I think he's immune to Power Break. What does work though is Protect, Cheer and Defend. Or you can capture him in which case he doesn't use Meteor. Or you can kill him with a counterattack, which he can't counter.