Zenn is friendly to Alliance players, but is still up to no good. The night elves of Dolanaar often find themselves punishing him for some minor misdeed by having adventures gather and feed him corrupted fruit found around the area (which results in a humorous transformation into a frog), but they have yet to resort to outright killing him as they do to most satyr.
CataclysmThis section concerns content exclusive to Cataclysm.
In World of Warcraft: Cataclysm, Zenn Foulhoof is chased out of Teldrassil for performing perverse magic and takes up residence in a cave near Cliffspring Falls; a cave that used to crawl with Naga. He is behind a taint corrupting the local wildlife, specifically bears and rats. As a result you are tasked with killing Zenn in the quest The Corruption's Source. He is aggressive to all players regardless of faction.