Upon running into him, he and Scherazard greet each other and the latter mentions they've worked with each other before, though Schera was still a junior bracer back then.
One of the jobs he's assigned to do is investigate the appearance of strange wolf-like creatures near the Krone Pass checkpoint; the same creatures who eventually attack the checkpoint en masse when Agate is staying there. He's later assigned to an escort job for a traveller from Erebonia.
On the surface, Sting appears to be the polar opposite of Scherazard. While Schera's a generally friendly person who's also a party animal when given the chance, Sting doesn't drink at all and has a rather brusque demeanor, but he still looks out for people around him.