From a random gamer conversation, but what if it wasn't lost, damned, or traitorous but stricken because of a clerical error that the administratum refuses to admit? It sounded like a joke at the time, but the more we thought about it the more it seemed plausible.
Chapter?
Screaming Geckos.
I'm not seeing your legion in our list.
We're the eleventh founding. Between the Iron Hands and the World Eaters.
Sorry, you're not on the list.
Not on the list? We defended the North Gate of the Imperial Palace on Holy Terra during the Horus Heresy!
Doesn't ring a bell.
Our Primarch slew a dozen greater daemons and turned the tide singlehandedly at the Tower of Secrets!
Still not finding you in the records.
What about my power armor, bolter and genetically engineered status?
If your chapter isn't in the records, it doesn't exist and is there for traitorus excommunicatus.
You guys are making a mistake.
The Adeptus Administratum doesn't make mistakes traitor.