|Battle Cry||Skovakarah uhl zarûn! (Redden the Earth!)|
|Chapter Master||High King Arucatas the Swordbearer|
|Specialty||Air-to-ground assaults, Drop Pod assaults, Being the Astartes version of the British SAS|
|Colours||Light blue with white helmet and aquila; Druids (Librarians, Apothecaries, Techmarines, and Chaplains) wear black armor with white helmets instead|
"Cousin. Do you use actual lions, celestial or otherwise?"
"Then shut up about us using spears."
- – Aaron Dembski-Bowden's take on the Emperor's Spears
Not to be confused with the Emperor's Scythes, the Emperor's Spears are one of those many, many chapters who nobody has ever heard of, or at least until Aaron Dembski-Bowden wrote a book about them, set after the Gathering Storm. They were one of the three Chapters stationed to watch over the Elara's Veil region (located on the eastern edge of the galactic core), the others being the Star Scorpions and the Celestial Lions. Unfortunately for them, the Star Scorpions were lost in the Warp and the Celestial Lions are still rebuilding after their spat with the Inquisition so they're more or less stuck watching the sector on their own. They are mostly Codex-compliant, but have dispensed with using the standard companies in favor of using autonomous warhosts, the better to cover the region.
Nemeton is a pre-industrial world dominated by vast oceans, and the Emperor's Spears' share the native tribes' superstitions about rain being a sacred gift from the sky, which annoys the Ecclesiarchy to no end. The Astartes interact little with them, and in turn the natives believe the Emperor's Spears' to be the spirits of lost children who take their young away never to be seen again.
Following a dispute with the Aurora Chapter over matters of honor that boiled over into a full scale conflict, they have become estranged from their primogenitor (who settled the dispute in the Aurora Chapter's favor; the Spears insist that they did so as an act of favoritism). The tensions have eased somewhat since then, but the Spears and the Aurora Chapter still refuse to fight together. Despite their badassery, they've not been doing too good lately, having lost half of the Veil to the Chaosified remains of the Star Scorpions, a warband known "The Pure".
ADB has given some details about their look and culture through some forums. They mark ranks with helmet plumes of various colors and are basically insular celts in SSPPPAAAACE compared to Ultramarines being space-romans, complete with the Ultramarines conquering Nemeton in the Great Crusade and trying to "civilize" the natives, building cities out of marble that the people of Nemeton never cared about and abandoned as soon as they could. The Emperor’s Spears have a distinctly Ancient Celtic theme, from their use of intricate knotwork decoration, Ogham Runes, Woad Blue colouring, organisation into semi-autonomous ‘Warhosts’ (akin to ancient celtic confederations, often with an elected uergobrit/vergobret, "over-judge") and their use of distinctly celtic-flavoured titles such as ‘High-King’ and ‘Druid’. Their allied forge world, Bellona, is also the name of a Gallo-Roman and Romano-British goddess of War. They also semi-worship the rain - just like modern-day britons.
When the Mentors sent Amadeus Kaias Incarius to ascertain that they and their Brother Chapter, the Celestial Lions, were still loyal to the Imperium, the Emperor's Spears of the 3rd Warhost under Lord Brêac were unimpressed with the fact that they showed up in a battered ship with zero reinforcements, especially when the Emperor's Spears and the battered Celestial Lions had been desperately trying in vain to contact the Imperium for reinforcements, holding out against Chaos forces that vastly outnumbered them. That and the Mentors wore the colors of their fallen Brother Chapter, the Star Scorpions, which led to Incarius being called the "False Scorpion" by the Spears. It turned out that the Mentors were also supposed to supply the two chapters with new technologies such as the procedure to upgrade a Firstborn into a Primaris Marine, which Incarius would release upon deciding that they were loyal enough, ironically being used on Incarius himself after he was captured and horribly mutilated by a Chaos Lord of The Pure in order to save his life. After Celestial Lions Chapter Master Ekene Dubaku was assassinated by a Callidus posing as one of the Mentors' serfs, Lord Brêac ordered Incarius and his remaining serf to be imprisoned, but the Druid (Librarian) Ducarius read their minds and confirmed their innocence. Lord Brêac and Incarius, with the help of the latter's serf, managed to slay the assassin and avenge Dubaku, and Incarius, disgusted by his chapter's complicity in the assassination and the Inquisition's plans to continue fucking over the Celestial Lions, cast off his colors to join the Emperor's Spears, becoming Vadhán, or "False Scorpion" in Low Gothic. The Emperor's Spears swore to fire upon any ship bearing the colors or heraldry of the Mentors or Inquisition, but with the Celestial Lions' command decapitated again (literally this time), the Emperor's Spears are faced with an even steeper uphill battle with no signs of reinforcements in sight.