The armies of the dead were made to be invincible and unrelenting, the un-life that beat in the center of their chest was supposed to provide the armies of the dead with infinite vitality, and battling them would be like striking at water hoping it would bleed, but nothing in existence were meant to withstand the onslaught of Primordials, and the Incarnation of Rowan inside the Cradle of Enoch would understand that this was partly due to the origins of the Primordials that predated the birth of Limbo and existence as a whole.
Their moves, which tore through existence, carried a power that the Beast of Final Rest could not understand, but one thing it had going for it was the fact that its armies and his deathly regions could be regarded as infinite.
It may have torn off a portion of its Will to discard the corruption from Xylos's attacks, but that did not hamper its power, more regions emerged from nothing and his armies further swelled.
