Veles did see the souls riding on the backs of birds, the emptiness in his land, the loneliness of Mokosh, and her longing gaze directed at the Surface.

And so he made an enemy for the birds, one connected to the Earth as they were connected to the Skies, as heavy as they were light and as grim as they were cheerful. Instead of a feathery down, he covered it with scales, instead of the ability to sing, he did order it to hiss, and instead of letting it fly wherever it chose, he took its limbs so that it couldst slither into every hole. And thus Veles appointed himself a messenger and called it a serpent.

And the serpents lurked for the human souls, ready to bite and strangle them, to kill their bird-steeds and swallow them whole. And when the serpent wouldst catch a human soul, it wouldst take it beneath the ground whence there was no means of escape.

‘Twas not long before souls swarmed in the Underworld, where Veles was their master. They were to keep Mokosh company for eternity, until the end of the times.