For a futuristic grim gory setting. Probably powered by some kind of dilithium battery or something similarly awesome. Anyways, basicly a big drill sticking up from a hilt that you primarily use for skewering enemies painfully and drilling through armor.
This ring keeps soul in the body even when the wearer is killed, making bringing life back to the wearer much easier. However, if it takes too long, the wearer will begin to rot and become undead. Removing the ring causes the spirit to pass on immediately.