It kind of hit me out of nowhere when I was waiting for the new ER. Why are you fighting shadows now? In first two Persona games you got your personas by talking to the demons and making them your minions (like in every other SMT game up to that point). It was fun and all but I cam see why they would want to do something different. Although this doesn't explain why all demons in P3 and 4 are trapped in cards and appear magically after battle. In P4 teddy sais that shadows are other sides of humans, so are personas but for some reason there isn't a single person who actually has a persona as his shadow self. Can someone clear this up for me? I'm really lost here.

Shadow are kind of the hidden ego everyone has. If you accept that hidden ego, you get a persona. Shadow's selfs, kinda transform into said persona after rejection.

It makes more sense if you look at each Persona game as a separate world from the others. Much like Final Fantasy, but less drastic.

I can kind of understand how they become persona users. It's the whole card thing I don't get. Do shadows become cards after battle or something like that?

The reason is because the first two Persona games sucked. Having to negotiate with the demons was stupid, and still is in the other games.

Aren't Personas and Shadows basically the same thing. And you can consider them demons if you want.

The shadow disappears and a persona pops out of thin air :p

And Persona 2 was fucking awesome back in the day, still is decent if you have patience.

The cards were always there in Persona gams, they are just a representation of that part of oneself, a type of focus.  The basic idea is that the cards the MC sees at the end of battle is his mind opening up to otehr possibilities

I guess we can talk about it but you most finish Persona 3 and 4 to get the point. If i remember right it was one of the major plot point of P3.

Personas and Shadows are actually terms which are highly referential of Carl Jung's work in psychology. This is very passively mentioned during a few dialog sequences in both 3 and 4 if my memory isn't going completely wonky. You might want to look at the wikis for them here and here in order to gain a basic understanding of the two terms as they were used by him. They'll shed quite a bit of light on how the latter Persona games apply them, if not to the extent of going into the card storage thing.