Canadian death metal act The Agonist on Thursday debuted a new video for "Gates of Horns and Ivory", the lead single from their upcoming fourth studio album.  Watch the video below.  The video marks the debut of the band's new vocalist, Vicky Psarakis, who replaced original frontwoman Alissa White-Glutz, who left to become Arch Enemy's singer last March.  Titled Eye of Providence, the album will arrive in stores on February 24th on the Century Media label.