There was a movie I briefly remember watching sometime between 2000 and 2007 latest I think.
In it I remember there being this man who was originally on the dark side and in the beginning I think we saw him kill a woman. Moving forward he takes on a couple of people to train them in what I remember to be a dinghy dark looking place that I think may have been underground but I don't know. He was teaching them to master the elements. Each person had control over one element. One fire or light (I can't remember which), one wind, one water and one was iron or something along those lines.
He was training them to fight the bad guys (the dark side) who he once worked for but we didn't find out till near the end of their training. I vaguely remember him basically telling them that it was time to fight the bad guys and that they were one short (so a missing element power) (the woman we saw him kill in the beginning) but they had no choice but to go on without her.
The group were asking where this other person was which is why he then basically explained to them that he was once one of the bad guys and he was assigned to kill her and that's why she wasn't there. Nearer to the end of the film the group and their trainer/leader went to what I seem to remember being a fairly dark rooftop type place where they were fighting the bad guys and ended up winning.
I realise this isn't much to go on but any help in locating the film would be amazing. If it helps I seem to remember the trainer/leader guy was bald. I could be wrong but I don't think I am. Many thanks for any help in advance.
PS. I could have been wrong about us seeing him kill the woman at the beginning and instead it would have been shown when he was explaining to his group what he did, although I do think it was it he beginning. Once again many thanks for any help on finding this movie :-)