Eliminator

Eliminators are the Vanguard Primaris Marines sniper specialists. They act as battlefield assassins for the Primaris Vanguard, using camo cloaks and specialised Bolt Sniper Rifles to pick off enemy leaders and disrupt infantry. They fulfil a long-standing gap most Space Marine armies have had since the Horus Heresy: a lack of dedicated sniper teams in power armour. Role-wise, they are heavier, more specialised sniper scouts designed to camp in cover and strike key targets from a distance (even through walls) with a range of special ammunition.

Equipment

Eliminators are full-fledged marines in stealth-modified Phobos-pattern power armour that has been stripped of some of its armour and fitted with silenced servos. In addition to their standard krak and frag grenades and bolt pistol, Eliminators all go to war with camo cloaks and signature bolt sniper rifles. Their rifles can accommodate a variety of special ammunition including:

Executioner rounds: The default ammunition type with high damage output, good armour penetration and a chance of inflicting mortal wounds.

Mortis rounds: Specialist ammunition that is extremely accurate and can target foes that are not in line-of-sight, but have reduced armour penetration and damage output. Used to eliminate foes that are completely out of sight.

Hyperfrag rounds: Fragmentation rounds for horde killing. No armour penetration, but basically converts your sniper rifles to a longer ranged boltgun so your special ammnunition isn't wasted on ork boyz.

Tabletop

For fluffy players of Raven Guard or Raptors who have long waited for a dedicated sniper unit, Eliminators are grand. Their competitive usage is yet-to-be seen, but they are notable for being one of the few infantry units in the game that can target foes outside of line-of-sight, meaning that plinking off a Guard officer behind a tall rock is now a thing.

They have the ability do deep strike, but this is at odds with their long-ranged fire support role. Their long range of their weapons makes deep striking less necessary and you want to have them on the board as long as possible, to maximise their damage output.

As a Heavy Support choice, they compete heavily with other units that could go into the slot and they lose ObSec, diminishing their value as objective campers. They are intended to be deployed as a fire support unit, not an objective holder (you have Infiltrators for that).

When entrenched in cover with their camo cloaks, they have comical durability - a 2+ save that ignores the first point of AP means that nothing short of plasma guns will even remotely threaten them. They also have the signature 2W of Primaris marines.

They are defined by bolt sniper rifles, which are a versatile anti-infantry weapon. With all ammunition profiles, bolt sniper rifles can target Characters at will. Their standard ammunition is a scout sniper rifle shot with AP-2 and D3 damage, instead of AP0 and 1 damage. On average rolls, Eliminators will have 2 damage per shot and a much-needed AP value for sniping. Their most unusual round is the Mortis round, capable of targeting foes entirely outside of line of sight at AP-1 and 1 damage. Mortis rounds also add an incredible +2 to hit to their attacks, meaning your snipers hit on 2's and ignore a single -1 to Hit penalty entirely. Their last round is a Heavy D3 36" boltgun for token horde clearing, but your points really are wasted every time you don't fire at a character with these weapons.