>>14954751>Sisters of the Nightingale? >mostly sisters hospitallerI'll begin on this. I'm the "I founded three Orders" guy.
Nightingale, I'd add an unit of specialist singers to that. They're mentioned in a line in Blood of Martyrs, and that'd tie up nicely in the name.
Founded in M38, around the same time as the Chapter.
Did we already decide where on Icelus it is located? This is important. What are they doing day-to-day? In Faith and Fire, a Hospitaller used to cure commoners, and we all know what that book's worth. Is there a pilgrimage location on Icelus? A historical sacred place, a relic, or what?
Do they go to war with the Chapter? I don't see very well Hospitallers working on Astartes physiology, we've seen examples of Sisters despising the Space Marines for being abhumans (do we consider that one too derp, as Astartes are a personal creation of the Emperor's?)
If they're Hospitallers, I'd easily see them as an offshoot of the Eternal Gate : they're forensics watching the Chapter for taint. Is this fluff-compatible? Rogue Trader era Sisters were there to police the Astartes. I'd see Apothecaries taking tissue samples as part of the geneseed extraction ritual (in 40k rituals conduct you), that will be later sent to the Sisters for analysis and the geneseed to Mars/Chapter vault.
Still needed for beginning :
Founder : name, institution, faction/sect, allies, enemies
Convent : size, commander, organization, history, characters
Cont.