Hmm, well it's been a few months since I seen the anime and I stopped around the mid point, I'm watching subbed so I could knock out the rest if needed. 

Right, I think we should go for Imperial Arms as well. As we seen in the anime even Night Raid lost people, they may be imperial arms users but they're still mortal. Plus remember how it goes? That when two imperial arms users fight, at least one will always die. I say if we do get arms then whatever enemy we face must also have them. 

As for what group we actually belong to, I actually like the idea of us being a completely different faction all together, although I'm not bought on just being another assassins' guild, but it is a nice starting point to build on.

Anyway my apologizes if this seems scattered and has bad organization, mostly just me throwing down whatever comes to mind.