[DJZen]

Spoiler: There's a man under the waterfall in the jade passage. He's on the lowest level up against the wall. Just walk behind the waterfall and you'll bump into him. He does sell Flare and Holy, but not Ultima. You don't have to do anything special to get him to appear or anything, he's just hidden behind the waterfall.

In SoR you can find him in the exact same place. I think he might not sell Holy this time around though.