After the Ancient Battlefield, Asura went to see the Burning Angel for a special mission. This mission was, of course, at the Chaos Cave.
Just like how Anna asked what they would do if a Primordial-Level Beast showed up, Asura also had that same thought in his mind, and so he went to the only person he knew could handle such a threat.
He wanted someone who isn't quite a primordial but can fight one. This way, if the primordial were to use Primordial Qi, the heavens would punish them, which would work to their advantage.
The Burning Angel had been working around the clock to finally step into the ranks of a Primordial for the past couple of months.
Klaus had given him his blood, and that had helped him tremendously. However, the Burning Angel is an overachiever, so instead of breaking through, he has been working to strengthen his foundation.
Atomic and Icon had already fixed all flaws in his body, so he was able to do more than he could before.
