Although both the Asura King and the Monarch are not good people, their duel for Ye Xunhuan is completely a dog-eat-dog situation he is more than happy to witness.
But he cannot watch the Asura King die, at least not currently, otherwise, if the Asura King were to die, the next target would likely be him.
After all, in this remote Wuling mountain range, even if Ye Xunhuan is killed, no one would know.
So for the time being, the Asura King absolutely cannot die.
Furthermore, Ye Xunhuan was not merely sitting on the sidelines watching the fight, he was also observing the Monarch's techniques. Although he couldn't make much of them in the end, after the Asura King and him fought for so long, the Monarch was somewhat worn out, making it safer now for Ye Xunhuan to step in.
