I hate knowing too much about a character, especially when a fact that is supposed to give you a better understanding of a character is taken, reworked, and expanded upon. In Pitch Black we know that Riddick was left for dead after being born. It's that fact that gives us an idea of who Riddick is: A victim of society who took the reigns of his hellish ride and deals with shit in his own way. My knowledge of Chronicles is limited as I haven't seen it since it was in theaters, but I recall that they took that one little fact and expanded on it and gave an explanation as to why he was left for dead. Suddenly what you think about him has changed. And not for the better in my opinion. Now we know he's some sort of special being of prophecy. Now he's the most important person in the entire galaxy.
But in the first one he's just a cunning thug who does whatever he can to survive, and ends up actually trying to help others in the process during his character growth.
Knowing that he's so amazingly important in the second film, completely changes his character in an abrupt and unpleasing way.
In Pitch Black, Riddick is awesome because he's just a man. Suddenly he's not just a man. He's a superman. Now his feats are less than impressive.
For an example take Star Wars and Midicholrians. In the first trilogy you attributed The Force to basically a magical energy that could be manipulated by those with the inborn talent. Science could not explain it, but it did exist. In the prequels we find out that ...yeah. Science can fucking explain it, and it's bacteria shitting out magic.
Now imagine one of your favorite characters. Let's say Indiana Jones. Suddenly you find out he's actually Hercules with amnesia. Bam. Fucked Indiana Jones up for you.
