The Cynrog were reptilian humanoids who hid behind masks. They worshipped the chaos god Balor.

Cynrog hid behind surgical masks with human eyes on top. They had technology capable of probing the subconscious. Other Cynrog technology created Nightmare Creatures from the minds of children.

In 1941, several Cynrog, led by Priest Commander Peyne, came to Britain and eventually Yns Du to bring back Balor, but by 2007 had failed. (PROSE: The Nightmare of Black Island)