He didn't choose to remain as a Child of the plane like her. He had chosen to become an Origin god and lose his title in order to preserve his life. He didn't trust others to protect him like Salvini did.
He believed that immortality was the best thing to rely on. Besides, immortality also allowed him to come and witness this fight. It is something he wouldn't have been able to do had he remained a child of the plane.
He came to see the famed Soverick, who defeated the Vipers during the Unified Skill Index. Apparently, he didn't die. Even more is that that little battle sage monkey is part of a multifaceted entity that everyone wants to lay their hands on.
What he saw was eye-opening and enlightening. He didn't dare join in the battle for fear of losing his life. After all, he is just a one-star Origin god. So he stayed at the very edge of the battlefield. But who would have thought that Salvini would appear beside him?