Xie Xuan is looking at Li Hua's hand. To be exact, he is looking at the flaws in Li Hua's attack.

are there any martial arts in the world that do not have flaws?

Maybe there are, but Xie Xuan hasn't seen it before. There are flaws in all the martial arts he knows, some of which are few and some of which are many. The same set of martial arts will also generate flaws to different degrees according to different people.

no matter how strong the martial arts are, it's still up to people to urge!

for example, in Xie Xuan's hand, even now, he can control his flaws...