Hsu (ウルムチ Ulmuch) is a minor NPC appearing in Golden Sun. He is a resident of Xian and a friend and possible romantic interest of Feizhi. He studies martial arts under Hama at Lama Temple, but while passing through Alpine Crossing he has the misfortune of falling victim to Saturos' trap. Saturos' party triggers a landslide to block the crossing and prevent Isaac's party from following them, (presumably unintentionally) pinning Hsu under a boulder as he was passing by. Feizhi's power of foresight alerts her to his dilemma, and she seeks help first from her father (who rejects her foresight and refuses to help) and later from Master Hama. While Hama is willing to help and is even able to reach to Hsu using Reveal, she is ultimately unable to free him from the boulder. If Isaac comes to free Hsu using both Reveal and Lift, Feizhi will give Felix's party the Golden Ring during Golden Sun: The Lost Age (provided, of course, that the player has transferred data from Golden Sun to The Lost Age).
- There is a mistranslation/continuity error in The Lost Age where Feizhi refers to Hsu as "Ulmuch", his Japanese name.
- The name Ulmuch likely comes from the city of Urumqi, the capital of China's autonomous region of Xinjiang (Uyghur).