Infiltrators are the Vanguard Primaris line infantry unit. The holy lovechild of a Reiver and a Tactical Squad, they are geared for extended recon and stealth operations behind enemy lines, with marksman bolt carbines, smoke grenades, omni-scramblers and the ability to take lite-Apothecaries in the form of Helix Adepts. They are for all intents and purposes, Space Marines who actually act like the elite shock troops they so represent. Finally after 30 years, GW has finally broken the cycle of Space Marines being depicted as morons charging into a open battlefield, or as autistic retards that are too stubborn to be able to have some improvisation. Now every Space Marine chapter is able to field entire units of Super Spec Ops. Raven Guard and Raptors are going to love the shit out of these hombres.
Infiltrators are all clad in Phobos-pattern armor, a variant of the Mk X Power Armor that is stripped down for lighter weight and modified with silent servos. Their backpacks are adorned with a variety of antennae and they go into battle similarly equipped to other Space Marines. Most notably, their bolt carbines have special optics that enhance their accuracy, they have smoke grenades in addition to the standard frag and krak grenades and omni-scramblers which can disrupt any kind of deep strike attack.
Infiltrators in many ways are the most disgustingly good Primaris units to exist. As Troops, they have ObSec. They can infiltrate (duh). They project a bubble forcing enemies that are set up as reinforcements to do so over 12" away, making standard deep strike charges completely impossible. Note that 'setting up as reinforcements' does not include abilities that move units across the map, like Da Jump. Their smoke grenades give the unit a -1 to Hit for a whole turn if the enemy fires ranged weapons at them at the expense of their shooting. This adds to their already high durability as 2W marines with a 3+ save. The option exists to add a Helix Adept, which is a combat medic for the squad. The Helix Adept has a weaker version of the Apothecary's narthecium, which lets it restore 1 wound per round to models in its unit, or revive a slain model in its unit on a 5+.
Their marksman bolt carbines are also fancy. They have a standard boltgun profile, but all unmodified To Hit rolls of 6 instantly hit and wound, letting you skip the wound roll entirely against enemies and grants a 1 in 6 chance of automatically wounding ANYTHING in the game from ork boyz to titans. Granted, AP0 means that wound isn't too likely to stick on anything whose save is better than a 4+, but it does make it more useful against things with high Toughness that a regular bolter would have trouble wounding in the first place.
In short: They are highly durable ObSec troops with solid killing power, the option to take their own personal mini-Apothecary, Infiltrate, and the ability to make enemy deep strikers around them totally unable to charge and deploy further than 12" away. They are a new gold standard for objective holding troops, and they have utility outside of that role thanks to their other rules. Their only real flaws are their difficulty in dealing with armored targets and their lack of options for dealing with foes in melee, both of which can be mitigated with proper support from other units. Also, they are expensive. Clocking in at a whopping 22 points per model and an additional 32 for the Helix Adept, it might be a good idea to plan your strategy around them if you plan to take more than one squad's worth.
|Forces of the Primaris Marines|
|Command:|| Primaris Ancient - Primaris Apothecary - Primaris Captain |
Primaris Chaplain - Primaris Librarian - Primaris Lieutenant
Vanguard Librarian - Helix Adept - Vanguard Lieutenant
|Troops:|| Aggressor - Hellblaster - Inceptor - Intercessor - Reiver |
Eliminator - Infiltrator - Suppressor
|Vehicles:||Redemptor Dreadnought - Repulsor Tank|
|Super Heavies:||Astraeus Super-Heavy Tank|