Trick is the mysterious old owner and bartender of The Dal Riata tavern, a "way station" that serves as neutral territory for the local Fae, and where all traveling Fae must check in and make their allegiances known. Politically savvy, if not politically ambitious, Trick is also a secret confidante and mentor of Dyson's, as well as Bo's grandfather (both were shocked by this news). Trick is also "The Blood King," a powerful Fae sage who can alter fate if he writes certain outcomes in his own blood. So, you know, don't mess with him.
(Source: SyFy)