Utterly Mad

Pbbbt. Alright fine, I was just fucking with you. <3

The basic idea is the assumption that whatever powers that breath weapon also serves as a more efficient method of deriving energy from food. Obviously there'd still need to be a lot of tricks to fudge the math enough to plausibly pretend the square/cube law doesn't exist, and the question of HOW some form of exotic matter-to-energy reactor develops biologically still basically requires "magic" as an excuse.

Now you've had your daily dose of madness.