We all know that Casdin and his followers left Lyon's chapter over philosophical differences in 2276. But what will become of them in the aftermath of Broken Steel? Assuming a heroic Lone Wanderer, at the end of the war the Lyon's chapter comes into possession of Adam's Airforce Base and a sizable amount of Enclave technology. That feels like it be a huge blow to morale, the whole reason they left was to persue the acquistion of technology and by rebelling they miss out one a huge cache of it.

But what will the Outcasts do? They can't change to the past only move forward.

Now lets keep in mind the Western brotherhood is a couple thousand miles away and has the NCR to deal with. They couldn't do anything about Lyon's even if they wanted to. They also left him incharge despite the change in direction he was taking.

Do they stay? try and go back west. Do the some of them up and leave both groups behind. I recall one member of the Outcast in the Bailey's Crossroads bunker commenting about leaving to join Talon Company. One thing I'm certain is they can't go back, They wouldn't be accepted and they'd be to proud to ask.

So what might the outcasts decide to do?

Having just played 3 again, because i finally got it stable enough to actually play, the one thing they basically say is that they want to report lyons for what he did, and that their the real brotherhood, and working on the premise that they are living by the brotherhood codex, their going to die, they dont have enough troops or a ratio of male, female for breeding just brotherhood, without going outside their group.

Plus they'll end up losing more, than they can keep up in rise of population, no amount of fancy guns or technology will help them if their death rate is higher than their birth rate, plus they need food and water.

Even if they start walking to try and return to the other brotherhood chance are again they'll lose more, if not all before they even get close.

They connect back with Western BOS. They aren't stupid and just wait to die off.