At level 10, this amulet can take the soul of one creature who is incapacitated one minute after hitting 0 hit points. The one attuned to this amulet can touch the creature and say the command word "Forever I shall hunt." and the creature's soul will be put into the amulet to forever be your quarry.
During battle, you can use a bonus action to unleash the soul of your quarry onto another creature of your choice that you can see using the command word "the hunt begins". For an hour or when that creature hits 0 hit points, any attack against that creature does an extra 1d10 of the weapon's damage. You also get advantage on any wisdom (survival) checks or wisdom (perception) checks you make to find it. After an hour or when the creature hits 0 hit points, the soul returns to the amulet.
At higher levels: At level 15, the extra damage becomes 2d10 and the duration becomes 8 hours.
You can unleash the soul 3 times per short or long rest.
Notes: Ranger