Therosaurus is the second genus of large tyrannosaur in subterramundus. Although not quite as big as sarcophaganax imperator, therosaurus makes up for it with a leaner build and longer legs. As its species name suggests, Therosaurus titanovenator is a titanosaur specialist like the extinct carcharodontosaurs. Therosaurus also has a long laterally compressed head with a locking mechanism in the jaws that allows it to hunt its massive prey. Additionally, the teeth are thin and blade-like as opposed to the thicker crushing teeth of its close relatives. This allows therosaurus to slice off chunks of flesh from titanosaurs and giant ceratopsians which are its near exclusive prey.
Although they prefer young individuals, therosaurus in prime condition are capable of taking down weakened adults of the largest titanosaurs. Their thick hide, feathered back and loose neck skin grant them protection from the fierce blows of titanosaur tails.
As they hunt larger prey than all of their relatives, therosaurus often leave behind massive carcasses once they have had their fill. As soon as the giants leave, scavengers and opportunists swarm the cadaver and pick off scraps left behind by the therosaurus. The carcass of a large sauropod attracts all kinds of carnivores including abelisaurs, pterosaurs, raptors, smaller reptiles and even juvenile tyrannosaurs. Various herbivores sometimes visit the kill sites to grab some bones for additional calcium.
Male therosaurus use deep echoing bellows and inflatable neck sacs to impress mates. Once a female chooses a potential mate, she will stay with him and watch him hunt. If she approves, she will join him and help bring down prey. If they work well together, the pair will stay together to raise many clutches of 5 to 10 young. These young will be independent as soon as they reach the size of a large dog. From then on they usually drift apart and search for a mate and territory of their own.