Hellraiser does do damage, just lower than average. The upside is that it drains lots of suit power of the victim, killing off their Armor protection quickly. With the shape shifter knife, if you press right mouse will aiming at a human, you'll freeze for a few secs, and if the human is still in your crosshair after that, you'll switch places with him, taking his body form until you attack. Just take note of the chat messages.