How this weapon got its magic is hard to say for sure. No magical blacksmith etched initials into the metal, and only small, simple runes identify it as having any kind of magical properties.
The prevailing theory is that it has been so long in the service of death that it knows nothing else. It yearns to bite through the flesh of criminal for that is why it exists.
As an action, You can choose a creature you can see and mark it for execution. You deal an extra 1d6 Slashing damage to the target whenever you hit it with an Attack from this weapon. If the target has a chaotic alignment, deal an additional 1d6 Psychic damage.
If the marked target drops to 0 hit points, you can use a bonus action on a subsequent turn to transfer the mark to a new creature within 60 feet that you can see.