The Engineer is a unique class that has no equivalent in vanilla XCOM, though they borrow some elements from the Grenadier Heavy and Support classes. Engineers are specialized in the use of grenades, with their starting Grenadier ability giving them two uses of each damaging grenade item they carry, and a bonus to grenade throwing range, and have several more perks to improve grenades further. Engineers also have access to perks improving their ability to destroy cover, and improving their use of the arc thrower.
Primary Weapons: Assault Rifles, Shotguns
Secondary Weapons: Pistols
Abilities
Rank
Ability
Specialist
Grenadier Allows two uses of damaging grenade items, and increases grenade throw range by 20%.
Confer -1 Mobility
Lance Corporal
Sapper +1 damage with AP and HE grenades, +2 damage with Alien grenades and triple environmental damage for all weapons
Smoke Grenade Carry a smoke grenade. Deploying a smoke grenade as your first action no longer end your turn.
Rapid Reaction Confers a second reaction shot, if on Overwatch and the first reaction shot is a hit.
No other bonuses.
Provide +1 Aim
Provide +2 Aim
Corporal
Holo-Targeting Shooting, flushing or suppressing enemies also confers a +10 Aim to any allies' attacks on those enemies.
Dense Smoke Smoke Grenades have increased area of effect and further increase units' Defense by 20.
Sharpshooter Bonus +10 Aim against enemies in full cover, crit chance +10% against all targets.