7. The Ancients
One of the first Ancients you encounter in GoW, the Soul-Eater and his stone-y pals are hulking rock golems that fire elements from their chest, exposing a weakness that Kratos can take advantage of by knocking pieces off and chucking them back inside. The Ancients as a whole have existed since the beginning of time in their rockin' bodies, with Soul-Eaters being ones that have gotten corrupted along the way and now feed on the life force of the creatures they kill.
Looking directly at their appearance then, that these monsters are quite simply humanoid rock formations lends itself pretty nicely to the Ancients' protection of nature itself, imbued with the power of the elements in a way that suggests they are mother nature's vanguard against any and all that would desecrate the world they reside in.
This seems even more likely when you take into account that the beasts are harmless unless you get in their way. If you antagonise them, then they fight back - otherwise they're happy to stomp around their own territories doing their thing in peace. A part of the old world and deeply connected to its beginnings, Ancients are a reminder that the environment itself is infinitely strong, and won't go down without a fight.