Capítulo 1078: The Eye

Every Progenitor, as well as everyone on the Transcendence Stage, had something special, a unique power, or even a philosophy towards the rest of the world. 

Obviously, the most obvious example was Alucard with his abnormal regeneration that didn't obey the rules of this world, but that didn't mean it was the most powerful feature.

Liang's mysterious power or Sven's devastating power with limitless attraction might have been more dangerous, as well as Gael's scars.

Ereg was the Progenitor, and he made Gael give his word that he would fight seriously, so he too, had to have something in response to Gael's scars. 

Otherwise, it would be the end for Ereg, as Gael would easily defeat him by simply overwhelming him with his superior physical strength.