Luckily i stumbled across this guy as Lv7 so i knew where he was when i started the quest. He's fairly easy, i beat him as Lv9 so you shouldn't have much trouble at all.
I've attached a picture of the Teldrassil map and i've painted some directions on it. The 'X' is where a Moon Well is, so it'd be blue on your mini-map, you can't miss it if you follow the trail i've painted.