Well I'm not in the clan completely, but I'll run over my ideas.
Make the armband ofc, but make the background transparent so you can layer it over your original bicep texture. Also, you may want to keep it more minimalistic, instead of swords and such, how you guys are brainstorming, I think plus marks and stripes would be more appealing. Also, you don't want to make them different colors by rank because then it would be a mess, you want them all similar. So sort of what I'm saying is, you want to add the extra stripes and plus marks in a way to portray the rank ofc, but also in a way that only origin can tell what the stripes and plus marks mean, I'm saying this because we don't want c/p swords on an armband with "general" or something wrote on it, that would look like we pride ourselves as a clan by rank when we should all be uniform like a family. Hope this was easy to read!