If you want to introduce a new character to an ongoing campaign, you can tie them into your story immediately by having them be related to a previous character. Whether that previous character died, or disappeared mysteriously, or got captured and is awaiting rescue, it provides a hook into the personality and motives of the new character.
Commentary by memnarch (who has not seen the movie)
Hm. I wouldn't have thought that Finn would have a lot of evidence he'd need to dispose of as a double agent. Especially since he'd been unconscious in the infirmary since the previous movie. Maybe the medical staff didn't realize what they were looking at if that's the case? Or maybe the GM's having the NPCs pretend not to know to "see what he does". I think that'd be amusing for Annie to run into that situation, especially if it's not one she'd planned out.
This looks like Finn's gathering a bunch of supplies before trying to escape the ship. I'd also thought for a moment that he'd grabbed the lightsaber in panel four before remembering that's already shown up with Luke and Rey, so now I'm guessing it's a blaster of some kind. Maybe Finn was previously just on the fence of Resistance versus First Order and is now only trying to save his own skin?
And hey, there's another one of those gold medallions. I guess the original focus on it was set up for it to make another appearance here with Rose then. Fair enough. I don't know if it'd work well as a movie plot bit for side characters, but now I also think I was a little harsh on the whole previous scene because of the abysmal bomber performance. Hmmmm. Set-up in order to have a touching moment of convincing Finn to stay and help perhaps? Maybe a stretch, but I could see that fitting in.
Edgar: Right, gotta make a pile of cash. Where’s Finn?
Finn: I’ve skipped out on the briefing.
Finn: While everyone’s busy, I’m collecting anything that ties me to being a double agent for the First Order.
Finn: Seeing the attack on Leia has made me commit to the Resistance. So I want to make sure none of this comes back to bite me.
Finn: I sneak down to the escape pods to jettison the evidence.
GM: With Tallie dead, Ben do you want a new character in the Resistance too?
Rose: Sure. I’ll be Rose, the younger sister Paige talked about before she died.
Rose: I’m crying over my matching gold medallion, reflecting on the tragic turn my life has taken.
Rey: Is this a Ben versus Annie tragic backstory roleplay-fest?
Rose: Built on your idea!
Rey: Shoot me now.