Brawler

Deep in the back-alley ways of dive bars and city streets, Brawlers can be found providing security for bars, gangs, warehouses, docks, etc. Anywhere a person may want a capable no-nonsense heavy-handed slugger a Brawler can be found. Most adore the use of blades, or makeshift weapons, or even just their fists to overwhelm their opponents in the tight causeways of which they operate. This does not mean they are slouches on an open battlefield either they are big, beefy, and tough as boiled giant boar hide. These men and women delight in crushing their foes with physical might to crumple them into mangled piles of meat and metal.

In the clinch

The damage dice for your unarmed strikes and improvised weapons increase to 1d8+Str Mod, and you can apply your Sneak Attack damage dice when you hit with an unarmed strike or improvised weapon even though it may not doesn’t have the finesse property. You also don’t need advantage on your attack roll to use your Sneak Attack if the target of your Sneak Attack is a creature grappled by you.

Human Shield:

You have learned to manipulate the body of a grappled creature to make attacks against you more difficult to land. Moving a grappled creature the same size as you or smaller no longer halves your speed, and when a creature grappled by you would grant you half cover, you instead have three-quarters cover. Additionally, when you are hit by an attack while grappling a creature, you can use your reaction to force that attack to instead hit the grappled creature ignoring their own AC.

Kidney shot: 

You can use your Cunning Action to make an additional unarmed strike against a creature you are grappling.

Kiss the wall:

You use your surroundings to further punish the target of your grapple, slamming them into the walls, ground, or nearest large object (table, barrels, suit of armor, etc.). When you roll a 1 or 2 on a Sneak Attack damage dice for an unarmed strike you make against a creature grappled by you, you can reroll the dice and must use the new roll, even if the new roll is a 1 or a 2. The grapple ends after this attack.

You can only use these abilities once per turn equal to your proficiency bonus per grapple.

At level 6 your unarmed and improvised strikes ignore resistance to bludgeoning, slashing, and piercing.

Giant's toss

After moving a minimum of 10 ft. You can attempt to grapple a target within your unarmed strike range (minimum of 5 ft.), you and the target both jump up in the air, making the same movement and landing to an unoccupied space within 1/2 your jump distance of your previous location.  You drive the targets head into the ground the target takes 4d10 bludgeoning damage. The target also lands prone. 

Low blows

You make an unarmed strike to cripple your foe and to cause them to this strike deals an additional 4d6 bludgeoning damage. If the attack lands the target must make a DC 18 constitution save or take an additional 2d6 psychic damage as the pain floods their mind causing them to wretch and throw up. If they pass the save, they shrug off the blow without taking more damage than the original amount.

Adversarius

Starting at 17th level, you have learned how to immediately remove your grappled victim from the fight. Years of fights, scraps, and brawls have culminated in you becoming a Diabolical Champion of pain and punishment. With your skills sometimes the most straightforward or dastardly moves have proven to be the best and so this feature grants you the use of two abilities that you can use once per enemy.

Neck snap:

As an action, you can make a grappling sneak attack forcing the creature grappled by you to make a constitution saving throw. On a failed save, if the creature has 120 hit points or fewer its neck is shattered, and it dies. If the target has more than 100 hit points, it immediately takes 10d12 true damage. The creature has disadvantage on the save if they are surprised.

Knee knocker:

As an action, you deliver a monstrous kick your target's knee dealing 8d10 bludgeoning damage and force the victim to make a constitution saving throw. On a failed save the target's legs are shattered and their movement speed is dropped to zero and they will remain prone with vulnerability to bludgeoning damage. This condition overrides any resistance. On a successful save the target takes half damage.