Retrieve the Sun Pearl.
Shu, the spirit of water, is eternally young, as are all the spirits of Shen-zin Su. I have been friends with Shu all of my life, but I no longer have it within me to play with him. I am old, and lack the energy.
For all his complexities, Shu is simple to please: he desires friendship. When I returned to play with Shu each season, I would always bring a Sun Pearl as a gift, and then we would play together. You can find a Sun Pearl in the pools to the southeast. Perhaps you can be his new friend.