Hush is a former acolyte of the Red Church, now a full-fledged Blade. Apparently mite, he never speaks, due to his lack of teeth, removed at some point during his enslavement, and his atrophied vocal cords. Instead, he communicates through a form of sign language known as Tongueless.
The Itreyan boy assisted Mia in her final trials, through he'd insist they are not friends and he remains loyal to the Ministry. He attempted to capture Ashlinn at the Ministry's behest, though the girl escaped with Tric's help.