While this isn't an ally you'd pop into just any deck, this is a fantastic resource for Silvan decks. It might seem a little expensive but when you consider how Silvans pop in and out of play regularly, his ability will be used constantly. And he's one of few Silvans to have Sentinel, which is certainly useful.
Defender of the Naith
Ally. Cost: 3. 0 1 2 2
Response: After a Silvan ally you control leaves play, ready Defender of the Naith.
"We have been keeping watch on the rivers, ever since we saw a great troop of Orcs going North toward Moria..." Haldir, The Fellowship of the Ring
Trouble in Tharbad #65. Neutral.
He seems very fragile. Is his ability really that useful considering he'll die from 1 hit most of the time? — TrueLolzor 6
I agree with the previous comment - I've been avoiding putting him into Silvan decks because 3 is a lot to pay for 0 willpower, 1 attack, and dies in one hit when he defends. And how often are you really using his ready? Maybe on the turn he comes into play (assuming you're using Celeborn but not Galadriel), you can ready him after he quests? — estyles 21