Sanguine blade

The Sanguine Blade is an ancient technique developed long ago by a doctor in a small warring village. Through copious studies of blood via interactions with every wound you could imagine, the doctor started to be able to sense the weave with every drop. He could stem the bleeding from even the deepest wounds and operate on internal scars using the patients own blood as tools. 

After passing this technique down to a number of pupils, word spread to rivaling villages, who sent their own spies to learn the trade. After learning all they could of the Sanguine Blade, the spies used the technique to kill the doctor and all his pupils, shrouding this method from the world. These spies slowly developed these techniques to become the expert killers they are today. 

Bonus Proficiencies

When you choose this archetype at 3rd level, you gain proficiency with medicine and the poisoner’s kit.

Sanguine Edge

Starting at 3rd level, you are always equipped to kill. As an action, you may draw blood from yourself or an incapacitated creature to create a finesse weapon of your choice by sacrificing the weapons hit die from your health. The weapon lasts as long as it remains on your person. If thrown, the weapon reverts to its viscous state after impacting its target. 

You may have 1 Sanguine Edge weapon at a time, increasing to 2 at level 7, 3 at level 11, and 4 at level 15. As your mastery grows, so to does the effectiveness of your creations. Your Sanguine Edge weapon gains +1 to hit and damage rolls at level 7, +2 at level 11, and +3 at level 15.

Finger on the pulse

Starting at 9th level, you are almost impossible to fool and those friendly to you with a pulse would be lucky to have you in their presence if it weakens. You can sense the disturbance in heart rate when you are being lied to with a small margin for error, you have advantage on Wisdom (Insight) checks to determine if someone talking to you within 15ft is telling the truth. 

Likewise, you can hear the flow of blood in those around, where it is strong and where it is weakening. You have advantage on Intelligence (Medicine) checks to stabilize a creature with a pulse. 

As much, you have mastered your own blood flow. You may weaken your pulse to be undetectable for a number of minutes equal to your constitution modifier (minimum 1 minute). 

Sanguine Awareness

At 13th level, your mastery of the sanguine has enabled you to extend the range and abilities of your acute sanguine senses. Finger on the pulse now works to a range of 30ft. Additionally, you may use an action to focus your senses to determine the location of all creatures with a pulse within 30ft of you. As long as you have at least 1 hit point, you cannot be surprised by a creature with a pulse. 

Heartstopper

Starting at 17th level,  you sense the blood in your foe, beating ever so loudly in your ear. Even louder in vulnerable locations, covered by less protection. While within 30ft of a creature with a pulse, you critically strike on an 18, 19, or a 20.