Vrykolakos is the name for demons inhabiting the bodies of those already dead, using corpses as a kind of clothing to cloak their evil from those around them. They retain powers of demonkind, and have been observed to change shape into animal and human forms as well as to cause fear in those targeted. They can also breathe fire.
Overwhelming damage and the power of God are the only things which have been observed to be effective at disposing of them. Some of the residents of the covenant appear to be able to penetrate their disguise, but they are very much in the minority.
Five were originally speculated to have arisen on Thera. One was slain through a group effort and one by the grace of God. Three are still at large. It is speculated that Lord Tybalt and Lady Kuria have links to these foul harbingers of doom if they are not part of their number.