Tekken 6 why does jin fight kazuya

Jin fights Kazuya for the same reasons he always has, although I don't seem to recall anywhere in the actual story line where Jin fights his father. Anyway, Jin fights his father because he wishes to kill him, along with Heihachi, to rid the world of their evil. His original plan was to kill them both and then to kill himself as well because he also has the Devil Gene and the Mishima Bloodline curse. However he was never able to do so because he either had some sort of vision or thought, i.e. Tekken 4 he sees his mother, Tekken Tag he is unable to finish his father for unknown reasons. In T6 he wishes to destroy Azazel and himself along with him, although the ending suggests that he is not dead nor rid of the Devil Gene. Not sure what he planned for his father or grandfather if he had anything planned at all.