My chapter was a made-up one called Deathbringers -- all-black with minimal red details (like eyes) and some silver highlights. I should have a whole history written out somewhere from back when I was more keyed in to the story of the Imperium. Basically they started when the Emperor was searching the galaxy for the missing original Primarchs and he made a new one to help. Artificially accelerated to adulthood and pressed into action before his bio-engineering was complete, he was bonded with his life-sustaining armour giving him a skeletal appearance. He was relentless in his quest to find what had been lost and came to be known simply as Death because he'd cut down anyone or anything impeding his mission.
His chapter, the Deathbringers, were formed as he went on his quest to recover the Primarchs -- a quest which grew to encompass attempts to recover lost knowledge or artifacts from the Dark Age of Technology (or whatever it was called) and they don't actually fall under the Adeptus Astartes; the Deathbringers grew parallel to the other Space Marines but with a slightly different structure to reflect their different focus. As well as Marines, the Deathbringers count Imperial Guard and Agent forces among their number, plus have a unique allegiance with the Eldar of the Ashkente Craftworld -- I basically made it so that any factions that could be allied with each other (at least under the army list rules of the time) would be "allies" as far as the technical specifics of my army lists and points allocations would go, but on the actual game battlefield they were one, unified force.
I miss playing 40K... When my friends and I spread out around the country to go to different colleges, we didn't meet new people to keep our involvement in the hobby going and we just stopped playing games amongst ourselves as our lives went in different ways.
