Sá is my own genshinsona, with whom I'm positively obsessed! More on them below~
Sá is a Pyro catalyst user, they have a staff with many uses, not just magic: It serves them as an incense holder, a torch, and a helping stick to navigate the rough terrains of Jueyun Karst. They have a very spicy personality, but are also clueless of their surroundings. As a traveler, Sá has been to the entirety of Teyvat, and has left suspicious items all around the globe that the Traveller can collect. One of such is a theater poster that features their picture all the way in Snezhnaya.
Sá ran away from Natlan, and has a beat down cottage on the foot of Mount Aocang that serves as their permanent residence. You may find them washing in the springs near Cloud Retainer's abode (much to the adeptus's dismay), collecting chilis on the valleys of Liyue, or pestering Rhodeia for a "date".