Zog was a Triceraton and an ally of the Utroms prior to their rebellion.
In the IDW Comics, Zog was created from manipulated Triceratops DNA as an assistant to the Utrom Krang. However, after years of loyal service under the Utroms he and his Triceraton-brethren eventually lead a rebellion against his master, which together with the dwindling Ooze supply enabled the deathblow to the Utrom empire.
Later, Zog fought the Turtles in the Battle Nexus and joined them in a revolt against the Dimensional Council.