Riot is hiding Jinx's back story or what?

Ok remember Jinx says: "You think I'm crazy? You should see my sister!"?

Or when (the purple side shopkeeper from Howling Abyss) tells Vi : "You look like your sister! Er, wait, I'm not supposed to talk about that..."

Remember that Vi is not crazy tbh... and yeah some ppl say that Crazy ppl see normal ppl as a crazy guy... if that was the case why she isn't saying some one that is really normal like Cay? i mean they probably met each other because they are in the same City...

I think that Jinx and Vi had a separate sisters that looked like each other but not the same person or something like that.

I don't think that they are sisters TBH even tho they made it official... but Swain (new swain)... he made it more questionable. if Swain taunt Jinx he will say: "Faces... Fading in the flames... it was all her fault" idk that Swain is talking about Jinx killing someone or someone killing Jinx's beloved...

Vi didn't had a back story that would connect to Swains words...

tbh the way that they said in the interview was kinda like: hey you know what if any body ask us about Jinx and Vi just say they are sisters...

the way that he said "Her sister is in the game... her name is Vi" was just... idk... he responded so fast... it's not just right thb... i bet they are hiding some thing... OR JUST SCRAPED THE CONCEPT OF IT AND GRAVED UP ON HER here is the link:( https://youtu.be/20lcWfD58Vc?t=1h13m36s )

If anybody had a theory or something about this just let me know because i just love the connection between Jinx, Vi, Caitlyn, and i love to know about them more.

(sorry for my English btw) (and please don't drop hate on me this is just my perspective and my though on this story)