Master Nyunpa (ニェンパ Nyenpa) is the head monk at Fuchin Temple in the eastern portion of Angara. He is an Adept that possesses Psynergy powers, which he titles "Ki", and among his powers is his ability to subtly use Mind Read. While he teaches Ki to students at his temple, it is based on the power of the mind, in contrast to what Master Hama normally teaches at Lama Temple: Chi, based on energy of the body.
Nyunpa will notice Isaac's travelling group if they attempt to read his mind with their own Mind Read Psynergy. Nyunpa will grant them access to the nearby dungeon Fuchin Falls Cave by sending out a telepathic signal to his subordinate guarding the entrance. After Isaac's group passes the dungeon, they go back to Nyunpa and he tells them about what they will face in Mogall Forest below, explaining how they can use the Force Psynergy they acquired in the dungeon on the tree stumps containing Apes.
After Nyunpa sees Isaac off, he begins to fast and meditate for the world's sake, eventually withering away to death. The exact conditions to cause Nyunpa to be his withered, practically dead self are to first talk to him after having gotten the Orb of Force, then after you've gone through Mogall Forest, defeated the Killer Ape, and left the forest off its bottom exit, reenter the forest right back through where you exited, to the area where you fought the Killer Ape, then leave again. With this done, the next time you get to Fuchin Temple by traveling clockwise around Angara, you'll find that the location has updated.
In Golden Sun: Dark Dawn, the Ice Queen mentions that it was Nyunpa whom she tricked into helping her escape Passaj. His petrified body is shown behind the Ice Queen before battling her. After defeating the Ice Queen in battle, the curse she placed on Nyunpa is broken and he tells the children of the Warrior's of Vale, he encountered years ago about him leaving the Temple in order to travel the world and help those in need.