Since they came out in 5th edition, Sternguard Veterans have always stood out as one of the competitive unit choices in the Space Marine codex. With their solid stats, reasonable points cost (for their abilities), Special Issue Ammunition, and access to Special Weapons/Heavy Weapons/Combi-Weapons, they truly are the “Leatherman” of Codex: Space Marines, with the ability to to almost any mission you assign them.
While they are good against any opponent, I think Sternguard particularly come into their own when they are used against a Craftworld Eldar opponent. More specifically, they have all the tools (especially if you use multiple sqauds of them) to counter many of the most dangerous and common Eldar threats.
What really brings them up a level, however, is combining them with Psychic support, in particular Sevrin Loth, who can choose his powers from Biomancy, Telekinesis, or Telepathy dicsciplines. Of these, going with the Biomancy discipline and selecting Smite (Primaris, so get it for free), Enfeeble, Endurance, and Life Leech and then attaching Loth to a 9 man Sternguard squad in a Drop Pod can make for a deadly combination.
Give the squad two Grav Cannons/Amps and 7 Combi-gravs, then have the whole unit come down turn 1, cast Endurance on the squad, and engage your Eldar target of choice:
1 – Wraithknights — With Endurance on, the Sternguard gain FNP(4+) and Relentless, allowing them to shoot their Grav weapons to full capacity even when disembarking from the Drop Pod. That translates to 31 Grav shots, 15-16 wounds on the Wraithknight, 10-11 wounds after a 5++ save, and 6-7 Unsaved Wounds after FNP rolls. Thus, on average, the squad can kill a Wraithknight in a single volley. Even if they do nothing else the rest of the game, accomplishing that turn 1 should make them worth the investment.
2 – Jetbikes/Aspect Warriors with 3+ saves — Fortunately, even after they use their Combi-gravs turn 1, Sternguard still have many uses against Eldar, thanks to their other Wargear. With relentless Grav Cannons and Vengeance rounds on their Bolters, they have 10 Grav Shots/14 Vengeace Round shots that can target Warp Spiders, Shining Spears, Striking Scorpions, Windrider Jetbikes, and other Eldar units with a 3+ save. Grav shots inflict an average of 5-6 unsaved wounds and Vengeance rounds inflict another 6-7 unsaved wounds, plus Loth’s BS5 Plasma Pistol and Smite Witchfire might add another wound or two as well. This means that the squad will cause 11-15 unsaved wounds against these Eldar targets on an average round of shooting, which is more than enough to kill an entire squad a turn or, at worst, force Jetbikes to jink, still killing 5-8 models and making them useless for shooting next turn.
3 – Aspect Warriors with a 4+ save — When shooting at Dire Avengers, Banshees, Swooping Hawks, etc. Sternguard can use their long-ranged Kraken Bolts quite effectively. Between 10 Grav Cannon/Amp shots and 14 Kraken Bolt shots, the squad on average deals 11-12 Unsaved Wounds, easily killing the entire squad and likely any attached ICs as well.
4 – Rangers/Guardians in cover — With their 14 x Cover Ignoring Dragonfire bolts and 10 x Gravcannon/Amp shots, the squad inflicts an average of 6-7 Unsaved Wounds from the Bolter fire and 2-3 Unsaved Wounds from the Grav Cannons, so 8-10 Unsaved Wounds total, enough to kill anything but the largest Guardian squads.
5 – Vaul’s Wrath Support Battery — With up to 9 wounds, T7 for all against shooting, and a majority armory save of 5+, this can be a tough target for Space Marines to deal with (not to mention a dangerous one as well). Enter the Hellfire rounds. With 14 Hellfire bolter shots and 10 Grav Cannon shots, the Sternguard shoot inflcit between 10-12 Unsaved Wounds on the Vaul’s Wrath battery, killing it outright and removing that threat from their brother Astartes.
6 – Wraithguard/Wraithlords/Avatar — Between Gravcannon/Amp shots and Hellfire rounds (good old Poison 2+ here to deal with T6 and T8 opponents), the Sternguard cause an average of 7-9 Unsaved Wounds after the dust clears and all the Armor saves happen. Again, this means the Sternguard can take out basically an entire squad or a whole Wraithlord per turn. The Avatar has a 5++ to help mitigate the AP2 Gravcannon shots, but even he is likely to die on average rolling against this volume of shooting.
7 – Eldar Grav Tanks — Surprisingly, this squad can even be a decent counter to Wave Serpents/Falcons/Night Spinners, etc. The Gravcannons inflict an average of about 2 HPs/Immobilized results per shooting, taking away the Skimmers mobility and setting them up to be finished off by Loth’s Plasma Pistol and/or a follow-on charge with Krak grenades by the Sternguard (remember, with Endurance, they are Relentless, so they can shoot their Rapid Fire and Salvo weapons and still charge). Even squadrons of Grav Tanks can be quite vulnerable to this tactic.
So, you can see how potent and versatile the Sternguard are with Loth casting Endurance on them. Don’t forget, Endurance also gives them FNP(4+), so basically doubling their survivability against anything that is not S8+. If necesary, Loth can “tank” for the squad with his 2++ armo save, FNP(4+), and Eternal Warrior (though he only has 2W, so don’t go crazy with him and use Life Leeach to “regenerate” his wound if necessary).
The biggest weakness of this unit, outside of its mediocre mobility once it disembarks from the Drop Pod, is its dependance on Loth getting Endurance off. All the other powers (i.e. Smite, Enfeeble, Life Leech, etc.) are nice to have but in no way essential. Endurance requirs two Warp Charges, so it can be challenging to cast, especially if you have a limited dice pool and your Eldar has lots of Warp Charges himself with which to Deny the Witch (fortunately, he can only harness on a 6+ at best, since it is a Blessing power).
Overall, I would say that this battle group, used in efficient coordination with the rest of your army, can be a game-changer, particularly against a competitive Eldar opponent.