The most unusual character to play in any Borderlands, Krieg takes advantage of the way your health tends to yo-yo anyway and incorporates it into his mechanics, offering builds themed around taking damage, setting things on fire, and rapidly switching between different types of damage to build bloodlust stacks. If you've played a lot of Borderlands 2 already and want a decidedly different gameplay experience from the vanilla characters, Krieg is a good buy.