How old are these kids? Because those books get impressively eloquent as they advance, not to mention disturbing:

A creature of an older world maybe it was, whose kind, lingering in forgotten mountains cold beneath the Moon, outstayed their day, and in hideous eyrie bred this last untimely brood, apt to evil. And the Dark Lord took it, and nursed it with fell meats until it grew beyond the measure of all other things that fly; and he gave it to his servant to be his steed.

Are kids gonna love that or wonder what the hell he's talking about? I can't decide.