The Doctor

The Doctor subclass introduces a new combat mechanic, Bleed. You will also gain proficiency in medicine and survival. This subclass focuses on knowing the anatomy of certain foes and determining where the best place to strike is for critical hits and bleed spots. 

At level 3 you gain the "Bleeding Strikes" ability and the "Ph.D." proficiency in medicine and survival. 

At level 9 you gain the "Critical Wound" ability. As well as the "Anatomical superiority" ability.

At level 13 you gain the "Late Night Studies" ability.

At level 17 you gain "The Doctor is in" ability.

Bleeding Strikes

At level 3 using any type of piercing weapon against an opponent (that can bleed) will cause the opponent to make a DC 15 CON saving throw or have one stack of bleed on them. Any single opponent can have a total of 2 stacks of bleed on them. Each stack will be 1d4 damage. These wounds can be cured by healing spells but not potions. Only the use of a healer's kit can stop the bleed. Someone with bleed stacks on them will take the bleed damage at the end of each character's turns. You can only apply 1 stack of bleed per turn.

The number of bleed stacks increases at levels  9 (3), 13 (4), and 17 (5). 

The dice also increases by 1d4 at levels, 7 (2d4), 9 (3d4), 13 (4d4), 17 (5d4).

 

PhD

At level 3 you gain proficiency in medicine and survival skill checks.

Anatomical Superiority

At level 9 you can make a DC 15 medicine check to determine where on your opponent you and your comrades should strike. Bludgeoning damage now deals an additional 2d4 bleeding damage to the vulnerable bleeding spot. (This does not work on any bleeding spot, just the spot you made your medicine check)

Critical Wound

At level 9 making a DC 17 Medicine check, as a bonus action, you can deduce where the weakest point on your opponent is. Successfully doing so will give you advantage on your next attack on that specific location and will also increase your melee attack to hit by +2.

Successfully attacking and hitting this weak point has a 35% chance to sever whatever arm, leg, limb, tail, etc whatever the weak point was. If the server is successful the opponent will instantly take 5d4 bleeding damage and will need to make a DC CON 18 check to remain conscious. If the weak point is the neck/head it is a 2% chance to sever and instantly kill the opponent.

Late Night Studies

At level 13 despite being adept in combat your studies of different beings have been the main focal point of your success. Your intelligence may be limited to anatomy and medicine, but you have become the best at it. Thus resulting in you gaining the keen mind feat and expertise in Medicine.

The Doctor is in

At level 17 you gain the ability "Purge all".This one action will take your full turn. You may make an attack at a bleeding enemy with advantage, if the bleeding enemy has taken no less than 75 points of bleeding damage and you roll an 18 or higher, you instantly kill your enemy. The target cannot be healed back up by anyone but you by spells or potions. (This cannot be nonlethal damage)

Any curse that would cause the enemy to resurrect is canceled out immediately.