[member="tom"]
Welcome back!
Well, if your characters have some history on Chaos, you could put them through an incident that brings them to this time. perhaps they were captured and carbon frozen? Perhaps held prisoner in a deep, dark cell for these past few years? And then they come out into this new world where everything has changed. It could be an interesting story. If not, you could always scrap old ideas and come up with something fresh. Or, if a character was never active to begin with, just start that character over in this new setting.
As for how to get active, there is always the trick of finding a faction that suits your character needs. There are many factions about, and new ones popping up every day. For building characters, I would suggest keeping it simple in the beginning, then embellish over time.