The Bloodbite Ring boosts Bleed resistance (via Endurance) by 400%. The ring does not affect, nor it is affected by, resistance granted from armor. However, it does stack with weapons such as the Bloodshield, Gargoyle's Halberd and Gargoyle Tail Axe.
The Bloodbite Ring is of limited use in PvE due to the small amount of monsters that cause significant Bleed build-up, but can be useful when equipping the Lifehunt Scythe. It is marginally more useful in PvP, where bleed weapons such as katanas can be popular.
Because it grants a bonus to the maximum amount of the bleed meter, it gives the illusion that the player's bleed meter fills up when equipping the ring. The phenomenon is explained in detail on the buildup page.