Seriach's gift is the power to summon and control hell hounds. As an action, the beneficiary of this dark gift can summon and control two hell hounds. Both hounds appear at the same time. The beneficiary can summon hounds only once, and the dark gift vanishes when they die.
The beneficiary gains the ability to speak and understand Infernal, if he or she doesn't already know the language. (The hell hounds understand no other language.) Sulfurous smoke issues from the beneficiary's pores whenever he or she speaks Infernal.