The vyes also posses wolflike ears and various collors - from simple black and brown to darkblue to redish brown. In their human form their only sign that they are vyes are their dark eyes simillar to polar bears, as said by Max McDaniels, but they also can make themselves look a bit like humans in their wolf forms.
Vyes, althought being the most common soldiers in Astaroths army, are very weak warriors and are often cowards. But their strengh grows with their numbers, and they are also almost always working in pairs or groups - it may even be a suggestion that these groups and pairs are families, because of the refferences of the two imaginary vyes to each other as "Dear", and because of Astaroths mark to Max like "their cousins"- and are able to bring down even as strong enemy as Bob. But their cowardish, servilian nature and easy gaining control of them makes vyes easy foes. They also, acording to Cooper, love riddles