Virule ("Vai-Rule") is the Demon Queen of Decay and Disorder. She oversees the Aging process of many things, and if she desired could speed it up with a Venom secereted by her Claws and Vines. However if injected into another Demon... it mutates them, making them more feral or leathal exaggerating their features or causing them to grow Mentally unstable.
The worst part? She does this sometimes simply for Self Amusement, and more then naught, its in Vain.