When I say complex, I mean a character that feels almost truly human, that has many issues going around him that make him act in very unpredictable ways.

To me, Krelian from Xenogears is the most complex character. This is no ordinary bad guy. He went from idealist scientist to a madman who wants to 'create god' because of the death of a woman he loved but was in love with his best friend. He went from a diehard rebel against Solaris to the driving force of that country exceeding even the powers of the Emperor, only to betray all of them in the end. He was trying to 'create god' but also trying to create the 'slayer of god' at the same time.

He was a big question mark for me. Who's your most complex character?

I'll say Alex fom Golden Sun:

he never helps is "comrades" Saturos/Menardi, Karst/Agatio, Chalis/Blados though he is always shown as a man with immense power(specailly after Golden Sun: The Lost Age) then he always helps the protaginist(s), I can't see what his motive are(specailly after Golden Sun: Dark Dawn)

The best recent example is Nathan Drake but making a cocky character is kind of easy. Still, it's as if he's an actor.

I loved the characters in Heavy Rain. We didn't have much background about their life but we get very much attached to them.

And of course most characters from Rockstar games are great (GTA, Red Dead Redemption).

"When I say complex, I mean a character that feels almost truly human, that has many issues going around him that make him act in very unpredictable ways."

If doing it this way, IMO the best answer would be Jowy Atreides from Suikoden 2.

I'm not going to say why, because of spoilers, but yeah... He is my answer.

Companion Cube. 

Super Mario.......just look at his issues.

No matter how many times he saves, and risks his own life he still can't get Princess Peach. 

He's hard working. 

Liquid Ocelot.

Not a doubt in my mind about the complexity of that character.

your description of complex doesn't match your description of the character imo. Your descrption doesn't sound at all like someone who is truely human. Although maybe if you mean most sporatic. 

Anyway I would say the most realistic characters would be from a rockstar game like previously mentioned. GTA4 or RDR.

I'm going for Terra from Final Fantasy VI.  SPOILERS AHEAD!

She is originally brainwashed by the bad guys and forced to do their bidding, once the device controlling her is taken off, she's pretty much a blank slate, but enough of her past is in her head to remind her not to trust anyone, so even when she's presented with a truth, she doesn't know if she should believe it.  deep down inside she doesn't know what is right or wrong, and it causes all sorts of problems for her and everyone else in the game.  this issue is compounded by the fact that she's not only the post powerful and important character in the game, but she doesn't even know what side she's on.  

Eventually she does pick a side, and does decide to fight with you, but she's struggling with herself right up to the point her past is revealed and it's clear what is right...but then she has issues balancing the ends and the means, coming to the conclusion she is harming people by fighting, and considers herself somewhat responsible for what happens midway through the game, she leaves your party to do the one thing she absolutely knows can only be seen as pure good: Protecting a city of children whos parents have all been killed by the bad guy.  the only way to get her back is to convince her that the best way to protect these children, and the children of the world is to rejoin you in your campaign against the world's true evil, a decision that still plagues her becuase she doesn't like the idea of leaving the kids alone, unattended.  

i think mario from all of the mario games