Pugilist

As a pugilist, you are a fighter like any other, but you rely on your body for offense and defensive instead of utilizing weapons. You differentiate yourself from monks by relying on the strength of your body and technical fighting prowess instead of the more nimble, acrobatic, and disciplined ways of a monastic tradition. Though, as a pugilist you are very likely to get along with a monk, and many monks are interested in the ways of the pugilist and vice versa.

Unarmed Training

Beginning when you choose this archetype at 3rd level, your unarmed attacks use a 1d6, increasing to 1d8 at 5th level and 1d10 at 11th. Additionally, you can use your bonus action to initiate a grapple against an opponent, and against targets you have grappled you can use your bonus action to make an unarmed strike with a damage die of 1d4.

Armored Savant

Starting at 7th level, while wearing magical armor or donning bracers of unarmored defense, unarmed strike made count as magical and gain a +1 bonus to attack and damage rolls, increasing to +2 at 11th level, and +3 at 15th level.

Haymaker

Starting at 7th level, you may make a number of Haymakers equal to your proficiency bonus per short rest. Haymakers count as regular attack rolls, but they deal an additional weapon die of damage, and on a hit, your target must make a constitution saving throw equal to 8 + your proficiency bonus + your strength modifier or be stunned until the start of your next turn.

Steel Body

At 10th level, you gain expertise in the Athletics skill, and additionally, you count as one size larger while making contested strength checks, which increases to two sizes larger at level 15.

Unbreakable

At 15th level, you learn how to efficiently grapple targets in order to avoid risk to yourself. Any time a grappled creature deals damage to you, roll 1d12 plus your con mod plus your proficiency bonus and reduce the damage they deal to you by that amount, to a minimum of 1 point of damage.

Invincible

Starting at 18th level, you gain the ability to avoid most of the damage dealt by a grappled target, gaining resistance to damage dealt by a target who you have grappled