In Tiantai teaching, inhabitants of the six worlds (hell beings, humans, demons, gods, etc.) are all fated to rebirth (samsara).
Only the three additional realms—sravakas, pratyekabuddhas, and the Buddha—have reached a level of existence beyond rebirth.
And on other realm, bodhisattvas, could also be beyond rebirth except that bodhisattvas have chosen to remain in our world to help everyone reach nirvana.