Bloodletter

Those that follow this archetype are not the squeamish sort as their specialty runs beneath the skin. Although gruesome, bloodletting is a precise art that requires years to master. While many rogues go for a swift kill, Bloodletter rogues prefer to see their enemies die slowly.

Hematologist

You are an expert in blood medicine. When you choose this archetype at level 3 you gain proficiency in the medicine skill and with the medicine kit. If you are already proficient in medicine you may choose another rogue skill in which to gain proficiency.

Rupturer

Some of your class features will require targets to make ability checks or saving throws. Your bloodletter save DC is equal to 8 + your Wisdom modifier + your Proficiency Bonus.

Hemorrhage. While wielding a light, finesse weapon such as a dagger, whenever you would deal damage with your Sneak Attack feature, you may forgo any number of sneak attack dice and rupture the arteries of your target. At the beginning of each of the target's turns, roll the number of sneak attack dice applied to bleed. The target takes necrotic damage equal to the rolled result. Each time you hit a bleeding target with a sneak attack, you may forgo any amount of dice rolled again, adding to the total number of dice rolled at the beginning of the target's turns.

At the end of its turn, a bleeding creature can attempt a medicine check to stop the bleeding. The DC of the medicine check is equal to your bloodletter save DC. A successful check ends all bleeding. A creature within 5 feet of the bleeding creature can also use its action to make a medicine check to stop the bleeding.

Undead, oozes, and constructs are immune to the bleed effect and critical hits do not double the number of sneak attack dice you can apply to bleed.

Transfusion

Beginning at 9th level, your knowledge of phlebotomy allows you to transfer illnesses between creatures. As an action you can end one disease or one of the following conditions affecting a creature you can see within 5 feet of you: blinded, deafened, paralyzed, poisoned, or stunned. The next time you inflict bleed on a creature, you can transfuse the condition to the target. The target makes a constitution saving throw or is affected with the same condition.

You can use this feature a number of times equal to your Wisdom modifier before taking a long rest.

Crippling Wounds

Starting at 13th level, you have learned to make the wounds you inflict even more deadly. You have advantage on attack rolls against creatures that are bleeding. Additionally, whenever a creature with the bleed effect moves they must make a constitution saving throw or take 1d6 damage for every 5 feet of movement it takes. For example, a creature that moves 20 ft takes 4d6 necrotic damage on a failed save. A creature that succeeds on the saving throw is immune to this effect until you you cause it to bleed again.

Sanguine Soul

At level 17, you are a master at spilling the blood of your enemies. Whenever a creature you caused to bleed is hit with an attack, they take an extra 1d6 necrotic damage. In addition, if a creature fails a medicine check to stop the bleeding of a creature you have caused to bleed, all future medicine checks to stop that creature's bleeding are made with disadvantage.