My guess at the upcoming end-game plot:
Jaryuu is the real Jaryuu but just with lost/altered memories and powers (which is what I'm guessing this person at the end is actually saying). Reiko will end up chilling out / control her powers a little bit because of her time with Jaryuu, but she'll still be acting crazy. We know that powers that aren't in control makes someone into a Jaryuu, at least from what that one captain/knight person said. So basically Jaryuu will end up becoming the actual badass Jaryuu he was but lose his sanity and gentle side because of it. And then Reiko will stop him because she's learned over time that Jaryuu doesn't want to be that way. Just a guess and it'll be a while till that happens as Reiko hasn't learned to chill just yet other than when she started losing control of her powers before and asked for help.