The Immortal Phoenix is a Divine Beast that existed for over six hundred years. It was defeated by Tian in the past, but was reborn and fought with Zi Shou against the gods. The Immortal Phoenix currently resides within Shi Xing who is currently in the Realm of Void.
The Immortal Phoenix was a powerful sacred beast. Thousands of years ago, its physical body was destroyed by Tian. He bounded his transcended vigour to the ancestor's family of Wu Geng. Because of this boundary, the Immortal Phoenix is able to ressurrect itself, everytime when it is defeated. Its divine power is primordial strength and only Tian was the only known god, who was able to defeat it more than one time.