Before meeting the Flame King, Chaos had already heard a lot of stories about him. They claimed he was someone on the same level as him.
They claimed he had single-handedly held back a beast tide that had ten Demigod-level beasts when he was merely an Immortal Lord. They said many things about him, each one sounding more unbelievable than the other.
Eventually, the stories started to include some other people, whom Chaos later came to know as the 24 Dragon Guards.
Before meeting the 69 Void Beasts and recruiting them to become his guides while inside the void realm, who later became his team, Chaos actually saw the 24 Dragon Guards as the most disciplined and terrifying team he had ever met.
The day he and the Flame King met, they fought a great battle. In the end, Chaos defeated him, barely, but he was soon ambushed by the 24 Dragon Guards. He knew he couldn't defeat them, so he made a run for it.
