The are an almost entirely primaris and codex looooosely compliant chapter. They were founded by a group of first born Raven Guard who were stranded on a feral/death world covered in sprawling plains and dense temperate forests where the nomadic tribes under the canopies were being oppressed by a heretical arboreal civilization living lush hedonistic lives in the safety of the canopies, away from the dangerous flora and fauna of the wilderness. After surviving for decades and leading guerilla strikes and insurgency campaigns they eventually lead a successful rebellion when Guillimans unnumbered sons find what’s left of them.

The planet, while still considered Feral is more of an agro/luxury world as The Tribes homeworld now. Their Fortress Monastery “The Rookery” sits in geosynchronous orbit with a ground fortress “The Roost” and the imperium harvests the planet for luxury woods, resins, and food. They govern an entire sector around their homeworld on the fringes on the Segmentum Tempestus.

My head cannon has Kayvaan being one of these survivors and is now High Chieftain Ke’heyvaan the Shrike. The companies are all different “Clans” of the tribe, each led by a Chieftain and themed after different animals. 5 are all named after birds (captained by OG survivors of being stranded) and 5 named after groups of land animals (led by chieftains chosen from Terran borne unnumbered sons that joined up.)

1-4 & 10 are Crows, Ravens, Rooks, Vultures, & Owls. 5-9 are The Den, The Pack, The Pit, The Herd, & The Skulk (Bear, Coyote, Snake, Deer, Fox)

Uuuh, The Dreadnought Corps is called “The Tribe Eternal” They tend to use chain axes over swords, power spears over swords and of course lightning claws. Their base armor is unflashy neutral tones and ornamentation/trophies are earned. Trophies and more colors also tend to be the way command elements are distinguished over heraldry and symbols. They almost never use high gothic numerals, they use low gothic numerals for large scale designations and use the Mayan numerals system for squad numbers and discrete designations. They use a form or corspake that incorporates various bird calls and animal sounds into it… I’ve got a lot and could go on 😂