Aliens

Cleaners

Rank	Armor	Health	Time Units	Accuracy	Strength	Reflexes	Bravery	Type	Body Size	Abilities
Agent	0	40	50	42	50	50	50	Living	Medium
Agent (Vest)	15	40	50	42	50	50	50	Living	Medium
Soldier	0	60	50	42	50	50	50	Living	Medium	Gas Immune
Soldier (Vest)	15	60	50	42	50	50	50	Living	Medium	Gas Immune
Leader	0	50	50	42	50	50	50	Living	Medium
Elite	15	65	50	45	50	50	50	Living	Medium
The General	0	45	50	42	50	50	50	Living	Medium

Cleaners are the first enemies you encounter, and they are not particularly dangerous.

The most common type of troop is the Agent, the white-shirted humans who are initially unarmored and equipped with weak Cleaner SMGs. These struggle to penetrate the heavy Tactical armour variant, so soldiers with Warden Armor can absorb a lot of SMG hits before dying. After a few weeks Agents with rifles and / or body armor will start to appear - these are more dangerous, but still relatively easy to deal with.

Cleaner Soldiers pose more of a threat. They wear green hazmat suits and gas masks, and are a little tougher than regular Agents. However, they start out with ballistic rifles and will be equipped with Magnetic Rifles when encountered as reinforcements on timed missions. Magnetic Rifles hit a bit harder than standard rifles and have better armour penetration, so you should treat them with respect even if you have Warden Armour.

In the Cleaner Base mission you'll encounter Soldiers with both Magnetic Rifles and body armour, and the combination of the added toughness and the close-quarters nature of the map can cause problems - a 3-round burst from a Magnetic Rifle can easily kill one of your soldiers outright if the Cleaner rolls well.

Cleaner Leaders have slightly better stat lines than the Cleaner Agents, but they never have body armour so they're nothing to worry about. The unique "The General" enemy character that appears in the inital ATLAS Base mission is also technically a Cleaner, but he's the weakest of the bunch given he's only equipped with a pistol!

It's worth capturing one of each type of Cleaner alive, as you get an Operations Point bonus (and some bonus interrogation research text) for doing so. It's worth capturing The General alive on the ATLAS Base mission for the same reason.

Sectons

Rank	Armor	Health	Time Units	Accuracy	Strength	Reflexes	Bravery	Type	Body Size	Abilities
Scientist	0	42	60	42	40	75	40	Living	Small	Psionic Triangulation (+30 Acc)
Soldier	5	55	60	42	40	75	50	Living	Small	Psionic Triangulation (+30 Acc)
Warrior	10	85	60	46	40	75	55	Living	Small	Psionic Triangulation (+30 Acc)
Elite	15	135	60	50	40	75	60	Living	Small	Psionic Triangulation (+30 Acc)

Sectons are small grey-skinned aliens that usually appear alongside Psyons (their larger cousins).

Sectons have low HP, relatively low Accuracy, and are usually equipped with weaker pistol-class weapons rather than rifle-class weapons. However, their Small size makes them a little harder to hit than normal enemies and they have very high Reflexes, meaning they will overwatch fire earlier than most enemies and are hard to hit in melee unless Supressed first.

Their ability Psionic Triangulation grants the Secton +30 Accuracy if they are within 8 tiles of a Psyon, immediately transforming them one of the most accurate enemies in the game. A purple glow around the eyes makes it obvious when this ability is active. This can cause problems inside UFOs, where the cramped conditions mean Sectons are frequently in close proximity to Psyons and their high Reflexes mean they are likely to overwatch fire at the Xenonauts coming through the door (or, once the UFO front door is open, snipe at the Xenonauts outside the ship).

There's a few solutions here. The low Bravery of Sectons mean they can easily be suppressed with a Flashbang. Alternatively, you can use their Psionic Triangulation ability against them by killing the Psyon - this will immediately suppress all "linked" Sectons. Or you can simply try and tank the limited damage from their pistols using a shield.

Psyons

Rank	Armor	Health	Time Units	Accuracy	Strength	Reflexes	Bravery	Type	Body Size	Abilities
Scientist	0	72	55	54	60	50	50	Living	Normal	Mesmerise
Soldier	10	72	55	54	60	50	60	Living	Normal	Mesmerise
Warrior	20	120	55	60	60	50	65	Living	Normal	Mesmerise
Officer	30	110	55	60	60	50	65	Living	Normal	Mind Control (80) Mesmerise
Elite	30	175	55	62	60	50	70	Living	Normal	Mesmerise
Leader	40	160	55	62	60	50	80	Living	Normal	Mind Control (100) Mesmerise
Pretorian	40	225	55	68	60	50	75	Living	Normal	Mesmerise

Psyons are large grey-skinned aliens with oversized black eyes and powerful psionic powers.

They are dangerous enemies that don't excel at anything in particular, but can do most things well. They are fairly tough and reasonably accurate, and are armed with rifles that pack much more of a punch than the pistols used by Sectons. Higher ranks of Psyon also have good Armour.

Watch out for Psyons in purple armour (Officers and Leaders), as both of these units are capable of Mind Control against units in their direct line of sight.

Mesmerise

All Psyons have the Mesmerise ability, which triggers if you attempt to attack the Psyon from within its vision cone and miss (if you're firing a burst or using a shotgun, only one shot has to hit to avoid triggering Mesmerise).

When triggered, Mesmerise forces the shooter to take a Bravery check - if they fail, they lose all remaining Time Units that turn. This can be frustrating if you wanted to attack multiple times, or if a soldier loses the Time Units they needed to move to cover.

The Mesmerise formula is a random 100 roll vs (Bravery - 25) x 2. In practice, this means soldiers get 2% resistance against Mesmerise for each point of Bravery above 25, and become fully immune to it at 75 Bravery.

There's a few ways to play around Mesmerise. You don't need to worry about it if the Psyon is not facing towards the attacking unit. You should ideally use high accuracy shots against Psyons, and move soldiers to cover before attacking them. Suppressed Psyons cannot use Mesmerise either, and grenade throws do not trigger Mesmerise (as they technically target ground tiles rather than the units stood on them).

Mind Control

Mind Control allows alien units to take control of Xenonaut soldiers for one turn. The chance of success is based on a combination of the alien's Psionic Strength, the defender's Bravery and Morale, and the distance between the alien and target (longer distances give a lower chance of success).

If successful, the target Xenonaut will immediately become an alien unit for the remainder of the current alien turn, the next Xenonaut turn, and then the following alien turn. The mind-controlled Xenonaut will only gain Time Units at the start of the second alien turn, which means you have one full Xenonaut turn to either run away from the Mind Control victim or to knock them out (as you can revive them with a medikit if they are stunned).

It is also possible to break Mind Control by killing the alien responsible, which will immediately return the affected Xenonaut to your control with full Time Units. This is often the best way to deal with the situation given the Psyon responsible will be nearby (as their Mind Control requires line of sight), but Leaders and Officers are tough and have good Armour so killing them in a single turn is not always possible.

Mantids

Rank	Armor	Health	Time Units	Accuracy	Strength	Reflexes	Bravery	Type	Body Size	Abilities
Scientist	0	55	75	54	45	55	35	Living	Small	270-degree vision arc Chemical Immune
Soldier	0	55	75	54	45	55	40	Living	Small	270-degree vision arc Chemical Immune
Warrior	0	80	75	54	45	55	45	Living	Small	270-degree vision arc Chemical Immune
Officer	0	60	75	54	45	55	45	Living	Small	270-degree vision arc Chemical Immune
Elite	0	120	75	60	45	55	55	Living	Small	270-degree vision arc Chemical Immune
Praetorian	0	160	75	60	45	55	60	Living	Small	270-degree vision arc Chemical Immune

Mantids are fast, agile insectoid aliens with high Time Units and a wide 270-degree vision arc, which makes them very difficult to flank or sneak up on. They have no natural Armour and only moderate HP, but their high mobility lets them close distance quickly. They are immune to chemical/gas effects.

Some Mantids are armed with Bio-Rifles and Bio-Cannons, which fire living Symbiote projectiles (see below) rather than conventional ammunition. Their low Bravery means they can be suppressed relatively easily, and their lack of armour makes them vulnerable to any weapon once you can land a hit.

Be aware that the basic Bio-Rifle requires 51% Time Units to fire, so a Suppressed Mantid cannot launch a Symbiote at you! (Unfortunately the same is not true for the Bio-Cannon.)

Symbiotes

Rank	Armor	Health	Time Units	Accuracy	Strength	Reflexes	Bravery	Type	Body Size	Abilities
Symbiote	0	20	40	60	35	40	80	Living	Tiny	3 turn lifespan

Symbiotes are small melee-only living weapons fired by Mantids equipped with the Bio-Rifle and Bio-Cannon weapons. With only 20HP, they are easy to kill - and they will die 3 turns after being spawned even if you won't kill them yourself.

However, Symbiotes can inflict quite a lot of damage in their short lifespan - their bite attack does a lot of damage against early-game armour, and can cause a lot of Bleeding Wounds. Symbiotes become less of a problem later in the game due to the poor armour penetation of their attacks, but as each bite destroys 10 Armour on the target and the Bio-Cannon spawns two Symbiotes per shot, you shouldn't ignore them completely either.

Most weapons can kill Symbiotes easily, but the pistol or a grenade are usually the most time-efficient way to deal with them. Also, Symbiotes have relatively low TU, so if all else fails you can always just run away from them.

Symbiotes can't jump over obstacles or climb through windows, which can be beneficial when trying to avoid them.

Remember Symbiotes are crushable, so vehicles and the Colossus Battlesuit can kill them just by pathing over them!

Sebillians

Rank	Armor	Health	Time Units	Accuracy	Strength	Reflexes	Bravery	Type	Body Size	Abilities
Engineer	0	70	65	50	60	50	60	Living	Normal	Regeneration (50) 35% Energy Resistance -2% hit chance per tile
Soldier	0	90	65	50	60	50	70	Living	Normal	Regeneration (50) 35% Energy Resistance -2% hit chance per tile
Warrior	0	135	65	55	60	50	75	Living	Normal	Regeneration (75) 35% Energy Resistance -2% hit chance per tile
Officer	0	150	65	60	60	50	75	Living	Normal	Regeneration (75) 35% Energy Resistance -2% hit chance per tile
Elite	0	240	65	60	60	50	80	Living	Normal	Regeneration (100) 35% Energy Resistance -2% hit chance per tile
Leader	0	275	65	62	60	50	80	Living	Normal	Regeneration (100) 35% Energy Resistance -2% hit chance per tile
Praetorian	0	320	65	63	60	50	85	Living	Normal	Regeneration (150) 35% Energy Resistance -2% hit chance per tile

Sebillians are tough, reptilian aliens defined by their Regeneration ability, which restores a chunk of health every turn (from 50 HP/turn on the weakest ranks up to 150 HP/turn on a Praetorian). Combined with their naturally high HP and 35% resistance against Energy weapons (Laser and Fusion), this makes them very durable.

However, they are not invulnerable. Even the strongest Sebillians have no Armour, and killing them quickly means their Regeneration will not have a chance to trigger. Additionally, 35% of any HP damage sustained by any combatant (including Sebillians) is permanent and cannot be healed - so they can eventually be worn down even if they survive for multiple rounds.

Finally, their "poor eyesight" ability gives them a -2% hit penalty per tile of range. They are therefore most dangerous at close range and easier to deal with from a distance.

Wraiths

Rank	Armor	Health	Time Units	Accuracy	Strength	Reflexes	Bravery	Type	Body Size	Abilities
Scientist	0	72	60	59	55	70	50	Living	Normal	Cloaking Field
Soldier	0	72	60	59	55	70	60	Living	Normal	Cloaking Field
Warrior	0	120	60	65	55	70	65	Living	Normal	Cloaking Field
Officer	0	100	60	72	55	70	65	Living	Normal	Cloaking Field
Elite	0	175	60	68	55	70	70	Living	Normal	Cloaking Field
Leader	0	150	60	70	55	70	70	Living	Normal	Cloaking Field
Praetorian	0	225	60	73	55	70	75	Living	Normal	Cloaking Field

Mentarch

Rank	Armor	Health	Time Units	Accuracy	Strength	Reflexes	Bravery	Type	Body Size	Abilities
Mentarch	25	60	40	50	60	50	80	Living	Normal	Hovering
Heavy Mentarch	35	120	40	50	60	50	100	Living	Normal	Hovering

Androns

Rank	Armor	Health	Time Units	Accuracy	Strength	Reflexes	Bravery	Type	Body Size	Abilities
Soldier	30	50	55	50	80	30	100	Robotic	Large	35% Kinetic Resistance
Warrior	35	60	55	50	80	30	100	Robotic	Large	35% Kinetic Resistance
Elite	45	120	55	55	80	30	100	Robotic	Large	35% Kinetic Resistance
Praetorian	60	150	55	60	80	30	100	Robotic	Large	35% Kinetic Resistance

Reapers

Rank	Armor	Health	Time Units	Accuracy	Strength	Reflexes	Bravery	Type	Body Size	Abilities
Reaper	0	100	75	90	60	75	100	Living	Normal	Infestation Fearless
Alpha	0	200	75	90	60	75	100	Living	Normal	Infestation Fearless
Zombie	*	100	50	60	60	25	100	Living	Normal	Hatches into Reaper after 3 turns Fearless

Servitors

Rank	Armor	Health	Time Units	Accuracy	Strength	Reflexes	Bravery	Type	Body Size	Abilities
Servitor	20	60	70	50	60	60	100	Robotic	Small	Auto-Heal Ray Death Explosion (40 Dmg)
Heavy Servitor	35	120	70	50	60	60	100	Robotic	Small	Auto-Heal Ray Death Explosion (60 Dmg)

Cyberdrones

Rank	Armor	Health	Time Units	Accuracy	Strength	Reflexes	Bravery	Type	Body Size	Abilities
Cyberdrone	15	150	50	50	60	35	100	Robotic	Large	Frontal Armour (100) Acoustic Scanners Hovering
Heavy Cyberdrone	25	250	50	50	60	35	100	Robotic	Large	Frontal Armour (150) Acoustic Scanners Hovering

Eternals

Rank	Armor	Health	Time Units	Accuracy	Strength	Reflexes	Bravery	Type	Body Size	Abilities
Eternal	25	250	60	70	100	50	90	Living	Normal	Mind Control (120) Mesmerise Regeneration (100) Cloaking Field Hovering
High Eternal	50	500	60	63	100	50	90	Living	Normal	Mind Control (120) Mesmerise Regeneration (150) Cloaking Field Hovering Acoustic Scanners