The last member of this dream team is the Warlock. While he has a pretty powerful machine gun, he's real strength lies in the psonic powers. They allow him to summon most of the regular enemies to battle - different versions of the ADVENT, mechs (even Sectopides!) or beasts. Also - as any psonic unit in the game - he's able to take control over a soldier.
He also has two unique abilities. One of them allows him to summon 2 to 5 zombie-ghosts, which appear on the battlefield and approach the player's soldiers. Then they become armed - after one turn, or after getting killed, they explode, damaging nearby units. Oddly enough, the Hunter can use this ability throughout the whole map, even if the alien units have no vision on your soldiers. The other ability is kind of similar, but it summons Spectres of a couple ADVENT soldiers - they generate a shield for the enemy, which renders him immune to all attacks. The shield only disappears after all phantoms are vanquished.
You should keep the following rules in mind when facing the Warlock:
- Remember that he'll try to pester you with his phantoms even without established eyesight.
- Don't cluster your units - the Warlock has access to a powerful area attack that will get many units.
- If you know you're going to fight him, make sure your soldiers have items that offer some defense from psi abilities (limiting control), or to have your own, skilled psi warrior - this will dramatically reduce the Warlock's efficiency.
- Don't leave him with around 20% of health points, because then he's able to use the ADVENT phantoms summon skill, which will grant him a shield, effectively preventing you from killing him. If you cannot finish him in a single turn, get his health down to around 50% and wait until the other turn to definitely do him in.
- If he summons zombies and they become armed - distance yourself from them before exterminating the creatures; this will let you avoid damage.
- If you own the Alien Hunters expansion, you can use the Frost Grenade/Frost Bomb) - it freezes the enemy for two turns, which let's you get rid of her easily.