Pledgers to this oath are Cainhurst Vilebloods, hunters of blood who find dregs for their Queen of coldblood, particularly in that of hunters. Yet the corrupt are heretics in the eyes of the Church, thus subject to the wrath of the Executioners.
If an Executioner rings a Beckoning Bell and summons a Vileblood using a Small Resonant Bell, the Vileblood will turn into an adversary and have a purple aura around them instead of a red or blue.
These watchmen admonish those who have become addled with blood. Be they men or beasts, anyone who has threatened the pledgers of "Hunter" oath has an issue with blood.
If Hunter of Hunters rings a Small Resonant Bell and a Blood-Addled Hunter rings a Beckoning Bell, the Hunter of Hunters will turn into an adversary with a purple aura. The Blood-Addled hunter may be in any covenant or none at all to summon a Hunter of Hunters.
The "purple hunters" will have Hunter of Hunters, Vileblood, or Executioner above their name instead of Adversary.
The host of the world will have Vileblood, Executioner or Hunter of Hunters above their name instead of Beckoner
If a purple hunter and a normal adversary are in the same world they are hostile towards one another. This can be used to host three person free-for-all's.
Additionally, if two purple hunters of the same covenant and the same world, they are friendly to each other. This results in a "Reverse Gank".
A Blood-Addled Hunter is a player that has committed sin by killing a non-hostile NPC
There is no known way to remove sin. It is also unknown if sin transfers to NG+.