Wraiths are a late game enemy. They are the Aliens' elite shock troop, and for good reason. Not only are they physically strong and hard to kill, but they have the unique ability to teleport around the battlefield.
Wraiths appear alongside Ceasans. The Wraith's ability to teleport around the battlefield allows it to get into a good position to attack any human targets. This could potentially be deadly, but fortunately the teleporter uses up all of a Wraith's action points, exhausting them for that turn. It is not uncommon for a Wraith to teleport itself into a vulnerable position, making them easy targets for live capture.
Wraiths are moderately accurate, have good bravery and have a lot of health. The standard Soldier has 120 health. This can make Wraiths hard to kill.