XCOM 2: War of the Chosen's new enemies come in many forms. As well as the three Chosen antagonists, there a several new enemy types to be aware of in the War of the Chosen expansion.
These come in the form of The Lost, Advent units Advent Purifier and Advent Priest, plus the Spectre.
Some share similar abilities with their XCOM 2 brethren, while others boast whole new powers, weapons or mechanics. Here's how you beat them and the autopsy rewards from Dr Tygan's autopsy table.
If you need more help, our XCOM 2 War of the Chosen guide provides a breakdown on how else you can tackle the huge expansion.
What are they? Despite appearing as a brain-dead, shambling zombie-like horde, the Lost are the most interesting new enemy type introduced in War of the Chosen by virtue of the new headshot mechanic they bring with them. These once-human husks have long been left hollow by the chemical agents spread by the alien invaders during the events of Enemy Unkown. Now, they gather in great numbers in abandoned cities and represent a threat both to Resistance activities and ADVENT troops alike.
What do they do? They swarm. Wherever there is one Lost, there are many. They will periodically appear either in missions to abandoned cities or during SITREPs "The Lost" and "The Horde", they are also attracted by the noise and bright lights of explosions from grenades and environmental detonations.
Once they arrive, they move towards the closest lifeform, be it your own troops or ADVENT forces, and attempt to surround and melee them. There are tougher variations of Lost, ones with more health or that can move further, but they all follow a similar behavioural pattern and it's their numbers that make them dangerous.
How to deal with them? Where there are Lost, there are headshots. War of the Chosen introduces headshots as a means of dispatching multiple cadavers each turn and the mechanic runs on a simple premise: for every one-shot kill you score on a Lost, you'll have that action refunded to you. You can keep taking shots until either you miss, don't do enough damage to kill a Lost outright or run out of ammo and have to reload.
This makes Sharpshooters with powered-up pistols particularly effective at taking down the Lost, and makes Templars conversely ill-suited to doing so. Even in great numbers, the Lost can be dealt with by keeping a cool head and methodically picking them off, starting with those with the least health and working upwards.
Autopsy rewards (codename Limbo): Dissection of the Lost facilitates the building of Ultrasonic Lures, a new grenade type that emits sound and attracts Lost to it so that they gather in one place. They can then be more easily picked-off with headshots, or evaded entirely.
What are they? Introduced as ADVENT's answer to purging abandoned cities of the Lost lest their numbers become overwhelming, Purifiers are soldiers encased in hazmat suits and armed with flamethrowers.
What do they do? They burn, of course. Using their flamethrowers on Lost or on troops huddled in close proximity, they seek to set the world alight and watch it burn. Burning units take damage each turn and cannot concentrate to fire their weapon until they have hunkered down to extinguish the flames.
They don't tend to do a great deal of direct damage, but their ability to set things on fire, things that may then explode, and to disrupt your troops during combat makes them dangerous back-up for more directly potent threats.
How to deal with them? Upon death, there is a chance that the volatile flamethrower unit they carry on their back may explode. That can attract more Lost, as well as damaging anyone - friend or foe - in the vicinity. The explosion radius is a bit smaller than a standard frag grenade, but is big and powerful enough to dissuade melee attacks. Treat with caution and shoot from a distance.
Autopsy results (codename Piezo): While flame-retardant armour would seem a natural discovery from this autopsy, Dr Tygan's work on this specimen shows that it's actually the skin of the genetically modified Purifier that make it immune to fire damage, not its armour.
As such, no flame-proofing is possible as a result of this autopsy, and instead you'll be able to build a slightly beefed-up version of a nanoscale vest that confers two points of health instead of just one.
What are they? Reclusive ADVENT troops that are increasingly seeing frontline action, these Psionic troopers have the ability to wield their powers either offensively against your troops or defensively to bolster their own allies.
Seemingly aware of their own strengths and weaknesses, Priests will seek to exert their power of the battle from afar, often retreating to rear positions making them more difficult to deal with.
What do they do? The Priest will often seek to mind control enemies and then retreat away from the action, forcing you to hunt down them down and kill them to release your ally. Alternatively, they place one of your troops into stasis, temporarily freezing them while also making them immune to any further damage for the duration of the stasis effect.
When acting defensively, the Priest can imbue one of its own troops with a Psionic shield, or turn them into a Holy Warrior with increased stats. In all cases, killing the Priest will dispel the effects.
Countering that, however, is the Priest's ability to cheat death on one occasion by entering stasis themselves the first time a deathblow would be landed. This makes them immune to any further damage and allows them to exit stasis and take another turn, forcing you to wait before you once more hunt them down and end them.
How to deal with them? As a relatively weak unit that typically does not boast much in the way of armour or health, Priests can be dealt with relatively quickly provided that you get the drop on them and take the first move.
When they are dropped in as reinforcements, or enter a battle in which you're already busy they can be more wily. In either case, setting a soldier on their cases, particularly a mobile one like a Reaper, Skirmisher, or a Ranger with Run & Gun is an effective tactic to take them out before they begin disrupting the battlefield.
Autopsy results (codename Apostle): Far more useful and in keeping with the unit's abilities than the Purifier's autopsy unlock, the Sustaining Sphere is a passive one-use item that mimics the Priest self-stasis ability. By placing the soldier in stasis upon receiving a hit that would otherwise kill them, their health will not fall below one point. The Sphere is permanently removed from the soldier's inventory after activation.
If you need more help with XCOM 2's expansion, our XCOM 2: War of the Chosen guide and tips can explain everything you need to know, from how to beat The Chosen Assassin, Warlock and Hunter and the new The Lost, Spectre and Advent units. Combat them by learning about each new faction with our Reaper abilities and skill tree, Skirmisher abilities and skill tree and Templar abilities and skill tree pages, as well as learning about the new Challenge Mode, Resistance Ring, Ability Points, Fatigue and Bonds systems. Good luck, Commander!
What are they? Humanoid in form, it's only when these entities start moving that their amorphous nature is revealed. They break up into what could possibly be nanobots to move to their destination, before reassembling to attack. They appear to share similarities with the Codex, but have a different set of abilities to their Psionic cousins.
What do they do? They can traverse great distances to reach soldiers in cover. Once there they can fire upon them with plasma weaponry but far more likely and effective is their deployment of a Shadowbound ability. This knocks a soldier unconscious and raises a shadowy figure in their place that has the same health and weapons as its victim, before the Spectre moves away to hide or even enters concealment to make it very difficult to find them.
How to deal with them? Although not appearing to be Psionic in nature, the Spectre's Shadowbound ability follows a similar pattern to mind-control. However, the shadow copy can be destroyed without having to deal damage to unconscious soldier, and the soldier themselves can even be revived while the shadow exists on the field.
If the Spectre itself can be destroyed, this in turn will disperse the shadow-unit and revive the soldier. Like the Priest, units with high mobility are useful to track down the Spectre once it goes into hiding.
Autopsy results (codename Haunt): By using material recovered from a Spectre during autopsy, chief engineer Lily Shen has devised a portable refraction field that enables a soldier to cloak by entering concealment. This technology can only be used once per item, and the refraction field will be removed from the soldier's inventory after use.