Master Nyunpa 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.
Nyunpa later appears in Golden Sun: Dark Dawn, again in an NPC role. Shortly after the events of Golden Sun: The Lost Age, he chose to halt his meditations in order to travel, with the goal of helping the people of the world. During his travels, he came upon Passaj, and discovered the Ice Queen Stone. However, Nyunpa's open mind allowed the Ice Queen to take control of him, and Nyunpa was coerced into fleeing with the Stone. The Ice Queen directed him towards her ancient abode of Harapa Ruins, but the Monk's will was not completely subdued. In Harapa, Nyunpa worked to help the people there rebuild the ancient ruins into the town it is when Matthew, Isaac's son, and his friends arrive, nearly thirty years later. Eventually, however, he fell completely under the Ice Queen's control, and took her into the depths of the ruins. Here, the Ice Queen attempted to leave, but she found that she could not leave her stone, and so she forced Nyunpa to remain with her.
When Matthew's party of Adepts travels to the ruins and defeats the Ice Queen in battle, Nyunpa is freed from her control. His appearance shocks the Adepts, who initially believe him to be a ghost. He then demonstrates his mind reading abilities and explains his circumstances. Nyunpa then accompanies the Adepts out of the Ruins. Before leaving, he speaks to Matthew, noting Matthew's resemblance to Isaac.