Aahhh!

Turmul had never planned to cooperate with others from the start. After all, he had plans of his own, intending to become the Tiangou Chief after this. 

The only way to gain the power of all the Primordial Beasts was by devouring Hazak once she appeared at the Graveyard of Gods. After all, the Tiangou's power allowed them to gain the power of anyone that they devoured in the Graveyard of Gods. 

The Tiangou Chief was carefully nurturing the God Kings of various generations, intending to devour them once he obtained the powers of a Spirit Aberrant. 

That way, he would become the strongest Chief, one that ruled over all. 

But of course, as only Turmul had the capability to act thanks to the rule set by the eight Primordial Beast Chiefs, he had every opportunity to become strong. With that, he took it, devouring Hazak first, followed by Gegrafikan.