The bones in Zatiel's arms were broken and he could not allow himself to spend his golden flames to heal them. Because doing that will make his energy pool dangerously low, and maybe his runic set will be deactivated and although his natural regeneration abilities were impressive, the clash between the sword and spear started less than five seconds ago.
Because of that, the strength he could put on his sword was decreased and not enough to trespass the Angelic Paragon's impressive physical defenses, but Zatiel's sword headed to the exact spot where the beak of the Nether Crow had pierced.
Ignoring the pain in his arms, he used every ounce of strength in his body and buried the sword charged with an immense amount of negative energy into the Angelic Paragon's chest until it almost came out from his back.
