He is a member of Salem's group.
Not much is known of their relationship, but Watts appears to be loyal and respectful toward her.
He appears to look down on Cinder after she was defeated by Ruby. He greatly enjoys tormenting and angering her, especially since she is unable to talk back following her injury. Given his comments, they apparently had a preexisting rivalry prior to her injury as well.
Watts treats both Emerald and Mercury with disdain, derisively calling them Cinder's "posse".