|Mantis Warriors (previously known as Mantis Legion)|
|Battle Cry||For The Emperor! For Redemption! For the Mantis Warriors!|
|Number||Approximately 100 remain|
|Founding||8th Founding. Mid-34th Millennium|
|Successors of||Marauders (White Scars lineage)|
|Chapter Master||Khoisan Neotera|
|Homeworld||None (previously Ootheca)|
|Specialty||Guerrilla warfare, hit-and-run, misdirection aided by divination by their Librarians, tactical applications of twinlinked multilasers|
|Colours||Emerald green, Camouflage|
The Mantis Warriors (formerly known as the Mantis Legion) are Ninjas in SPACE. They were one of the chapters guarding the Maelstrom warp Storm in Ultima Segmentum. When the Astral Claws rebelled against the Imperium of Man, which came to be known as the Badab War, the Mantis Warriors joined them because they were allied for a long time and it seemed like a good opportunity for some ass-kicking. First they looted a Fire Hawks' ship, shattered the Marines Errant attack force, and lost when two other loyalist chapters kicked their asses.
Only 300 or so Mantis Warriors survived the fighting. They have been granted Empy's pardon (since the now-Red Corsairs were corrupted by Chaos, but no one knew about it) and sent on a 100 year penitent crusade during which they could not recruit new marines. The Space Sharks, with a silent acknowledgement from the Fire Hawks, took an entire generation of Mantis Warriors' homeworld denizens and forced them to fight to the death, taking those that survived with them to replenish their losses. The Mantis Warriors are notable for being one of the few chapters who used camo patterns on their armor - during the Tranquility campaign their armor had yellow and black tiger stripes pattern.
But most importantly, they are White Scars successors, which implies a heavy use of bikes (even though their Forge World rules don't give much incentive for that), have subtle Henshin influences, have a specific mutation that grant them extraordinary focus and combat skills during battles, and name their companies after giant bugs that live on their homeworlds. This means that it is extremely likely that at least one of them is a grasshopper-themed biker ninja with extensive bionic enhancements. Yep, the Kamen Rider exists in 40k. And it is awesome.
In the "Warrior Brood" novel of Leprechaun "Multilazzur" Goto, the Mantis Warriors are now seen as outcasts, but aren't Chaos or Renegade marines. While they were already given the Emperor's Pardon, the Imperium, being paranoid fucks to everything that casts a shadow, still holds a strong sense of distrust among the Mantis Warriors due to their treason during the Badab War, so their only real home in the grimdarkness of space is their Battle-barge. In the aftermath of their Herodian IV defense against the splinter Tyranid Hive Fleet alongside Deathwatch they were whittled down to about 100 dudes so the Inquisition decided to let the poor guys recruit more neophytes before the grimdark galaxy (read: their own paranoia) caused the end of their Chapter.
One other interesting trait of the Mantis Warriors is a gene-seed mutation similar to but distinct from the Blood Angels' Black Rage. Through deep religious meditation and acts of penance the Mantis Warriors can enter a state of supreme focus known as Battle Haze that gives them bullet time-style ninja reflexes. Problem is, the state is permanent and those who enter it spend the rest of their lives completely catatonic whenever they're not in combat. Those who have entered the Haze have their own special Death Company-inspired unit called the "Mantis Religiosa."
Forge World has released rules for all the chapters in the Badab War. The Mantis Warriors are... a mixed bag. First, their non-bulky models gain Move Through Cover and Hammer of Wrath and if they declare a charge while in cover, they gain Furious Charge. The whole army can also re-roll Seize attempts. It's an obviously melee-focused set but prevents terminators and jump infantry (traditional marine melee) from benefiting. However, it can be fairly puissant if coupled with pistol or shotgun scouts. For elite options, there's the honour guard or a veteran/command squad in an assault transport.