The Psi Operative is the last, fifth soldier class in the game, and the only one that you won't be able to access from the beginning of the game. To unlock it, check the "How to unlock the Psi Operative" chapter of this guide. The class focuses on the usage of psi power to increase the effectiveness of allies and to harass enemies. Psi Operative can only use an assault rifle, whereas the second hand is used by the item required to use psi abilities, the Psi Amp.
Another thing that differentiates this class from others is the lack of any limit when it comes to learning abilities - soldier of this class can learn all the abilities, provided that you have enough time to do so. Additionally, ability selection is not limited in any way as well - there are no "levels" here like normally, and each training of the Psi Operative lets you choose from 3 different abilities to learn.
Does guaranteed psionic damage to an organic enemy, ignores cover and armor.
Completely stuns the target for 1 turn, but renders them immune to any damage or attack.
Debilitating telepathic attack that can inflict different negative conditions, including mental control of the target.
Grant a bonus action immediately to a nearby squadmate
Using Soulfire now heals you for half of the damage dealt
Stasis can be used on friendly units
The Psi Operative is surrounded by an aura that immediately extinguishes or blocks any mental impairments for themselves and any nearby allies.
Once per mission, when the psionic soldier is reduced to 0 hit points, he is instead reduced to 1 hit point and put into stasis for 1 turn.
Insanity now does a small amount of guaranteed damage, and applies Rupture to the target.
The Psi Operative is immune to fire, poison, acid, and explosive damage.
If an enemy is carrying explosives, they can be remotely detonated by the Psi Operative.
Permanently mind controls an enemy.
Only one successful Domination can be performed per mission.
Project a beam of psionic energy that damages every target it passes through.
A large AoE ability dealing moderate damage and a chance to inflict insanity on all targets in the storm
Soldiers of the Psi Operative class don't have to worry about selecting proper abilities, because sooner or later they will have access to every single one of them, and recommending them also doesn't have any sense as you will be given access to them quite randomly.