Jopal Seer is located in the "Jopal Village," area of PoFire.
You can find Jopal Village by following the North wall after zoning into PoFire. It's the group of islands surrounded by Lava. The Seer in particular spawns on the North Eastern most island. It's a small island with a single, large hut. He's the middle spawn of the three mobs that spawn on the west side of the hut.