Let's start with the introductions. I think Selene you already know. It is why you came here in the first place right?
Michael Corvin is the toy that the warring vampires and lycans spend the entire movie playing around with.
Lucian is initially depicted as the bad guy, but he is actually the victim here. A victim of star-crossed love, no less.
Kraven is the useless guy really. He thinks he is in charge, but with or without him does not make any difference to the outcome of the plot.
Erika, on the other hand helps Selene to have her way to justice. And her chic gothic looks add a bit of a feminine touch to an otherwise gory outing. No offence to Kate!
Viktor (below right) is an old sod who is the one who has caused all the trouble in the first place. Which is why we are not giving him a complete wallpaper all for himself, eh? He also killed all of Selene's family and turned her into a vampire.
