I can't remember the title for this movie that goes like this: there are a group of warriors with different elemental powers. I think they're supposed to be the guardians of the earth or something like that. Then, one of the members of the group betrays the rest and becomes evil. I explicitly remember a scene where she is injured and offers her blood in some (satanic looking) ritual, and in turn her health is renewed and she becomes more powerful than ever. The rest of the warriors have to fight her. During their fight, the traitor becomes good again but has to die for some reason or other. So that's it, that's the best description I can give.