What the Heaven Devouring Avatar was using was the first mystique-like ability that Wu Yu had discovered. Wu Yu gave it a simple name: Return. 

What it meant was simple. That would be reflecting the attacks of his opponent. 

Obviously, there were times where the opponents' attacks were so strong that they exceeded the limits he could endure. 

Nonetheless, the limits he could endure could be frighteningly high at times. As long as the other party wasn’t overwhelmingly more powerful than the Heaven Devouring Avatar, he would be capable of completing an impossible turn-around driven by Wu Yu's resilience! 

Also, there were some attacking means that were more suitable for conversion, while others not as much.  For example, that little dagger that the opponent had would be the hardest to convert if used. Wu Yu's Heaven Devouring Avatar would definitely be pierced by it! 

However, for some attacks, it would be extremely easy and suitable for conversion. An example would be the attack the other party was releasing currently. The Offensive Spirit Design of the Ancient Soul Dreamlocker, Ancient Soul Dream D...