Traag is a character confirmed to appear in the 2012 TV series. He will debut in episode 17, "TCRI".
At 2012 San Diego Comic-Con, Traag was described as a being from Dimension X, made of molten magma and able to "vomit lava on people". He is also said to be 17 feet tall while the Turtles are only 5 ft.
Gallery
Concept art
Traag in TCRI