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.
A Wraith stands roughly 180cm (6 foot) tall and is probably the most exotic of the extraterrestrials encountered to date. Only vaguely humanoid, it has triple-jointed legs and a bulbous head with a glowing, fleshy protrusion on each side. Disturbingly, they are reported to possess the ability to teleport around the battlefield - allegedly even through solid objects.
Wraiths have a well-developed muscular system that is otherwise unremarkable, leaving them closely matched with humans in terms of strength and resilience. They possess four main internal organs, all of which are completely unrecognisable and appear to have hybrid functions. Each is protected by surgically implanted armour plating composed of the same materials used in UFO construction, though in this case it is only a few millimetres thick and possesses unusual flexibility. It appears both effective and unobtrusive; quite why subdermal armour is not present in other aliens we cannot say. This suggests these aliens have an important role within the alien hierarchy. Though I doubt we are looking at the alien leaders, the Wraiths may well represent the alien elite forces.
The vast heads of these creatures contains a thick skull reinforced with protective armour plate, underneath which lies an expansive brain. The glowing nodules on either side of the skull comprise largely soft tissue packed with respiratory cells that produce immense amounts of energy (the glow seems to be a side-effect of this). These biological reactions consume almost fifty thousand calories every hour and thus cannot be a product of natural evolution. The only plausible explanation is that it is fed directly into the bloodstream through the ubiquitous valves surgically implanted into the necks of extraterrestrial soldiers.
The other discovery of note is that these nodules sit atop an opening in the skull, meaning any blow of significant force would likely kill the creature outright (a bullet will certainly do the job). As the rest of the skull is well-protected, these nodules must be extremely important - likely linked to the power of teleportation. We plan to amputate them from any live specimen captured immediately to test the theory - if it does not teleport out of its containment tank once it regains consciousness, we will be proved correct. If not, I foresee having some difficulty interrogating the beast...
Amputation of the glowing nodes on either side of the prisoner's head appears to have stripped it of the power of teleportation - though I will retain the armed guards to ensure we are not being deceived. As usual, a summary of the creature's vulnerabilities has been distributed to your men and should increase their combat effectiveness by roughly ten percent.
The Wraith is a genuinely alien beast. While other specimens watch sullenly from inside their glass prisons as we work, our captive Wraith is distractingly twitchy - it refuses to expose its back to us, instead turning its whole body to face whoever is closest to the holding tank. If approached simultaneously from different directions, it will spin on the spot until they leave (for literally hours at a time if necessary). Your men find this hilarious, but it is utterly infuriating if one is trying to concentrate.
Ridiculous mannerisms aside, the Wraith scored excellently on all tests performed - demonstrating high levels of intelligence, superb sensory awareness and lightning reflexes. They are also capable marksmen and their physiology is deceptively resilient, even without their subdermal armour. The power of teleportation only makes them more effective; we have verified accounts of the beasts teleporting straight through the walls of a sealed room. Thankfully, there appears to be a limited range on this ability and the aliens take some time to re-adjust to their surroundings after having made a "jump", preventing them from firing their weapons immediately. Nevertheless, I suggest your soldiers watch their backs as closely as this beast guards its own.