Frankenstein

Knowing the weaknesses of your enemys Body is the Key to Victory. Most Frankensteins love to experiment on their enemys during Combat.

Bonus Proficiencies

When you choose this archetype at 3rd level you gain proficiency with the herbalism kit the poisoner's kit, and the Medicine skill If you are already proficient in Medicine, your proficiency bonus is doubled for all checks made with it. If you already have Expertise in Medicine, you gain Expertise in, one of the following skills instead: Arcana, Investigation or Nature. Additionally when you make a Wisdom (Medicine) check or use one of the tools granted by this feature, you can choose to use your Intelligence modifier for that check instead.

Expertise Arcana

You gain expertise in Arcana

Expertise Investigation

You gain expertise in Investigation

Expertise Medicine

Expertise in medicine 

Expertise Nature

You gain expertise in Nature

Proficiency in Medicine

You gain proficiency in medicine

Surgical Precision

At 3rd level your anatomical prowess lets you exploit openings in an opponents defense to inflict a debilitating injury on them.

When you would deal sneak attack damage on your turn, you can choose to decrease your sneak attack damage to inflict an Injury If you do so, the target must succeed on a Constitution saving throw (DC equal to 8 + your  proficiency bonus + your Intelligence modifier) or suffer one of the effects detailed below. An Injury persists until the start of your next turn. Starting at 15th level, your injuries don't expire at the start of your next turn, the target must instead make another Constitution saving throw against your Injury DC, at the end of its turn to end the effect.

You can decrease your sneak attack damage by 1d6 to inflict one of the following Injuries:

Hamstring. One of the target's speeds becomes 0.

Cut Tendon Sheath. The target becomes disarmed.

You can decrease your sneak attack damage by 2d6 to inflict one of the following Injuries:

Gut Shot. The target has disadvantage on attack rolls.

Nerve Cramp. Attacks against the target are made with advantage. 

Experimental Surgery

Starting at 9th level you can use the bonus action granted by your Cunning Action to use a healer's kit or make a Wisdom (Medicine) check.

Additionally you have learned to turn the Strengths of your enemies into your own. You can now implant parts of slain enemies into your or other living bodies. Each implant grants you one ability of the creature you have taken the parts from. Harvesting a part requires a successful Wisdom (Medicine) check. The DC equals 10 + 1/2 CR of the slain monster, this DC increases by 5 for each part after the first one and each part must hold a different ability. A Creature can have a number of implants equal to its Constitution modifier. Performing this surgery requires a number of hours equal to the monsters CR or half the CR if performing the surgery on an other creature. After the surgery, the creature has disadvantage on everything for a number of days equal to the CR of the used monster. You can remove surgeries this takes as long as if you would implant something and the negative effects are the same as if when you implanted the monster parts. A regenration spell or simular magic also removes the effects of the surgery.

The parts must come from a creature that has a challenge rating that is lower or equal than the CR or Level of the creature that receives and that is not more than 1 size larger or smaller than the creature that receives the implant. You use your ability modifiers for those traits. If you gain the regeneration trait, the regained hit points can't exceed your proficiency bonus.

This ability can't include legendary resistances, legendary actions, immunities, true sight or abilities tied to limbs or equipment that you don't have (like wings for flying). 

It's Alive!

Starting at 13th level you create a Flesh Servant from parts of fallen enemies. The Flesh servant is friendly to you and your companions and you can command it as a bonus action. The Flsh Servant tries to follow your commands to the best of its abilities. 

The Flesh Servant is a construct and uses the statistics of a Knight without any equipment, the leadership or the Parry ability, with 84 hp, 22 Constitution, 8 Intelligence and 8 Charisma, immunity to Psychic, poison damage and the poisoned condition and it can't be charmed. It understands every language you understand but it can't speak. It doesn't require food, water or air. 

You choose the size of your creation, this might require additional Body parts to function.  

 

Size	Dexterity changes	Strength changes	Features
Tiny	+4	-4	Hit point are quartered, can gain a fly speed via transplantation, gains Evasion
Small	+2	-2	Hit point are halved, can gain a fly speed via transplantation.
Medium	0	0	-
Large	-2	+2	Becomes a siege monster

 

If it drops to 0 hit point it dies, looses all transplantations it has and you need new body parts and a long rest to create a new one.  

You can never have more than one Flesh Servant at the same time. 

Modification Synergy

Starting at 17th level you gain a bonus to all saving throws equal to the number of implants you have. Your Flesh Servant also profites from this bonus if it has any implants.