Caim is the main protagonist of Drakengard, however he is widely considered a Type V Anti-Hero, which is basically what is known as "Hero in name only": in other words if Caim was not fighting an enemy far more brutal than himself he would be considered an outright Protagonist Villain.
In Drakengard 2, he becomes the antagonist, pursuing Nowe and his party. Nowe fought him and he won the battle. Later on, Caim contacts him into ending Angelus' suffering by killing her. Doing so is not only the end of her life, but also Caim's. He dies smiling at Nowe, thanking him for doing his duty.