If anyone watched some of the later episodes of Rurouni Kenshin, it was almost a duplicate character to one kid who was a total psychopath with no emotions that Kenshin couldn't "read" or "predict" the movements. That's pretty much where the similarities ended, though.
There have been small hints to some Gin backstory in the intro and during the SS arc with Matsumoto, and now she's obviously going to play a part in bringing him down just like 69-tattooed cheek guy (brain fart moment here on the name...) did with Tousen.