Specialized Killers

Witchers are trained in small batches, usually consisting of ten to fifteen kids, the vast majority of which don’t survive the training. They usually die to monsters, but even fewer survive the infamous Trial of the Grasses, the final part of the process, in which the subject is subjected to toxic chemicals which mutate them into something more than human, something that is both the evil they face and the silver they banish it with. The majority of witchers carry two swords with them. Silver for monsters, steel for humans. Both, for monsters.

Witcher Code

Despite the many differences between individual witchers, such as school, personal differences, and general worldview, one thing that unites all of them is the witcher’s code; the idea that a witcher doesn’t work for free. They’re not selfless heroes, they’re businessmen who provide an invaluable service to the community, and if there’s no gold to be had, there’s no witcher to be found. Although they hunt the demons that plague the people, they are hated and feared for their unnatural appearance, a constant reminder of the evils that lurk in the world. You will never find a witcher working a guard post for a fort, they are restless creatures, migrating across great distances, taking contracts as they go, and moving on.

Combat Casters

Signs
Starting at 3rd level, you gain access to signs, a form of magic only usable by Witchers. All signs require the use of one hand for somatic components (no other components are required). Sign casting is a very strenuous task and requires lots of concentration. 

Using signs is a strenuous activity. As such, there is a limited amount of times you can cast a sign in a turn. You are only able to use a sign as a bonus action. Sign casting beyond that is possible, but you take a level of exhaustion for each sign cast and it consumes an action, unless the sign is being used as a feature or ability. You can only prepare as many signs as equal to your WIS modifier.
Sign Save DC= 10 + Proficiency bonus + Wisdom Modifier

Aard
Prestidigitation: Out of combat, the Witcher can create disturbances in the air that extinguish small flames like torch and bonfires. As a bonus action, you blast a 15ft cone with telekinetic force dealing 2d6 force damage .The first two creatures hit within the area must make a strength saving throw against your Sign save DC. On a failed save the creature is knocked back 10ft, On a successful save the they are only dealt the damage.

Yrden
As a bonus action, you place a magical trap on the ground (20 ft range) in a 10ft radius, lasting 1d4 turns. All non-allies within the area of the trap have half movement speed.

Igni
Prestidigitation: Out of combat, the Witcher manages to create small flames that light candles, torches and bonfires. As a bonus action you send out a burst of flames in a 15 foot cone, all creatures within the area make a Dexterity saving throw. On a failed saving throw the target takes 2d8 fire damage or half damage on a successful save.

Quen
As a bonus action, you can cast Quen. You cast a protective ward around yourself, gaining resistance to bludgeoning, piercing, and slashing damage until the end of your next turn.

Axii
As a bonus action you blast a target's mind with psychic energy, the target must make a Wisdom saving throw against your Sign save DC. Upon a failed save the target is stunned until the start of your next turn and dealt 2d10 psychic damage. If the target succeeds the save they are unaffected by the Sign and gain advantage against this Sign for 1d4 rounds.

Specialized Killer: 

Witchers are master combatants when it comes to slaying all manner of creatures, you can choose one from the following: Abberation, Beast, Celestial, Construct, Dragon, Elemental, Fey, Fiend, Giant, Humanoid, Monstrosity and Undead. When fighting your favored creature type you immediately learn whether the creature has any damage immunities, resistances, or vulnerabilities and what they are. You can also take advantage on saving throws coming from your favored enemy and advantage one attack per turn. You can choose another enemy type at levels: 7, 10, 15, 18 and 20.

 

Occult Knowledge

Beginning at 7th level, when the hunt requires, Witchers can craft oils and concoctions to aid them in combat. You can spend 30 minutes and 5 silver pieces creating a blade oil to aid you in combat against a specified enemy type (see Specialized Killer list). You can create the blade oil for free and in 1 minute if the monster type is one of your favored enemy type. The blade oil does the following effects: deals an extra 1D8 per attack, and ignore any immunities/resistances the creature might have to your weapon. 

You have advantage on identifying monster types if you have clues such as tracks, blood or a witnesses that is able to give a brief description. If it is a favored enemy type you can identify the type of creature, not the specific creature immediately without a skill-check.

Mutated Reflexes

Starting at 10th level your mutations make you an apex predator of humanities enemies, Once per turn as a free action you can strike fear into the heart of your target until the end of your next turn, You can do this equal to your WIS modifier with a minimum of one. Additionally you gain the ability to counterattack when your prey tries to harm you. If one of your favored enemies forces you to make a saving throw, you can use your reaction to make one weapon attack against the enemy. You make this attack immediately before making the saving throw. If the attack hits, your save automatically succeeds, in addition to the attack’s normal effects.

Kaer Morhen's Finest

Starting at level 15, your known as a legendary witcher and an expert of martial combat and casting. When rolling initiative in combat that involves your favored enemy you are guaranteed one free attack against that target and take advantage on initiative. You can also never be surprised by any of your favored enemies.  

School of the Wolf

Starting at level 18, You've mastered the hunt and can teach your allies to combat the paranormal. When fighting your favored enemies you can impose disadvantage on your allies attacker and give them resistance to the incoming damage, you can do this equal to your WIS modifier. When using this feature you can move yourself in-front of your ally, if you choose to do this your enemy will attack normally with advantage in which you can use an immediate reaction to critically rebuke your attacker.