The Poison Spirit had not gone crazy. In fact, he was the one who asked Jiang Yi to let him fight. Now that You Tianni had acceded to his request, he naturally smiled.
Become famous with one move!
This was what the Poison Spirit wanted. He was prepared to go all out in the battle and to scare everyone with his prowess. He wanted to fight for the glory of the Phantom Race and allow the Phantom Race to see how powerful he really was. The Poison Spirit was prepared to fight aggressively and ruthlessly and take You Tianni as the Clan Head that had chased him out in the first place. Of course… he had to use this battle to return smoothly to the Phantom Race.
You Tianni's cultivation level was higher than his. He also realized more nomological laws than he did. This meant he had much greater nomological mystical abilities than the Poison Spirit.
Yet, so what?