The Thunderbird is the ancestral power of the figure of the second circle, a Family Chronicle (invocation) rooted in Native American mythology that ties the figure to Peysen and the Unnameable.
It appears as a colossal flying creature that navigates the perpetual storm over the surface of the Inferno, escorting its summoner in the descent through the Ante-Inferno. In the third circle it was ambushed and destroyed by Cerberus, and the figure had to continue alone.