The wrath of a serpent

Diamond beady preying eyes of black silk
Of silent evil and devilry that swirls within the creature
The darkest venom that boils in its fangs
A fountain of death now ready to spring forth for the kill

Cunningly she glides with the softest rhythm
While the night conceals her evil intent; the moonlight admiring her scaly skin
Beauty and innocence she portrays and wins the love of the weak
Toy and dance with her prey she must, it is only the prerequisite of what is to come
Calmly she encircles her next meal as though to embrace it

Till her gray fangs at last deep themselves, drinking the warm blood
Venom fast releasing to the quickest and darkest of deaths
This is an evil too black to describe with ink
Dark as it may be, this is the truth of what she conceals within
The portal to hell - the wrath of a serpent
But why did she ever befriend me at first?