Isis stone to wake a serpent

We four, bound by blood*
Standing in the crossroads
On the underside of the world
Waiting our turn
Here we see
Coiled serpent
Black and baking
In the sun
Stone is flung
Serpent wakens
Arrow of poison
Pierces our hearts
Teeth sink into tender flesh
Lightning strikes, too fast to see
We seek succor for the stricken
Pleas met with spiteful laughs
Slow advance, not to stir the poison
Its course fast and merciless
Merciless, merciless
In vast halls, buried in hurried hordes
No help found here, only dreadful tears