Berserkers

In that last moment, that last strike, Nehanda strike a stabbing motion with his hands toward Mary middle of the chest. 

He planted a poison on Pirate Lord Mary. 

And the price for beings of lose to the Pirate Lord Mayr was to have her punch through his chest and then grab his heart and pull it out from his chest, leading to his death

Mary crushed Nehanda heart in front of him before once again punching him in the face. But that poison is already there. 

That is why Wang Jian make a bet that she would not attack him without knowing the full effect of the poison she has been inflicted with. 

With his last breath he managed to make the famous Pirate Lord suffer such injury. Wang Jian could not help but admire such determination. 

Nehanda method is too rash but it also works. 

Wang Jian planned another method but even before that method could be applied Nehanda choose the fast but more destructive plan.