Revenants were a type of human bioweapon engineered on Sejm Island by the Uroboros research team under Dr. Alex Wesker.
Revenants were created during research on the virus, and were created by stitching together various body parts into a humanoid figure before infecting the mass. This resulted in a living organism of humanoid appearance, able to move each body-part as if its own, though they were noted for their form of movement, more comparable with a doll or puppet being manipulated than natural walking.[excerpt 1]
Following the demise of the research team in 2011, the Revenants were free to explore the ruined island. Though it is uncertain when precisely they escaped the mines, within six months they and other Uroboros mutants almost succeeded in wiping out all other life on the island. All Revenants are believed destroyed following a BSAA operation to sterilise Sejm Island.