[Taqwus]

Well, I'm away from the manual right now (on vacation still... but addicted to the forum it seems *shrug*).

They're Blood/Air, can fly regardless of storms, can fire off a lightning attack (some limited number of shots per battle), and have a melee lightning attack as well, if memory serves. Can't remember if they're ethereal, but might be. Oh, and they're lightning-immunes, of course.

The bit that makes 'em potentially useful against Rarku is that lightning attacks are universally armor-negating (even against basic innate protection, not just armor), and he's not immune, so it's a good way of beating prot-25.