I liked the portrayal of the High seer as a character and the ambience of the story.
The flesh-eater really came out of nowhere and felt a little "D. ex-machina". It might be fitting though, as it mirrors the surprise of the mawed down elves ;)
Maybe a hint or two in foreboding about the existence of the flesh-eaters on the planet would go a long way.
All in all I liked the story and it made me think about Eoin Colfer's writing style in the "Artemis Fowl" series.