Pugilist

Pugilism is often called the father of modern boxing. These fighters use their fists to inflict serious damage with devastating strikes. Pugilists can be found in a ring fighting to earn their keep, or they can be found in a back alley fighting for their survival. It is said that pugilists channel within them a form of inner strength achievable only with their own determination.

Fistcuffs

Starting at Level 3, you gain a damage die known as "Fistcuff". Your unarmed strikes can use the Fistcuff die in place of their normal damage, and your unarmed strikes count as melee weapons when needed for your fighting style, like Dueling or Two-weapon Fighting for example. In addition, when you hit an enemy creature with an unarmed strike on your attack action, you may attempt to grapple that creature as a bonus action.

From Level 3, your Fistcuff die is 1d6. The value of the Fistcuff die increases as you gain levels in this class, increasing to 1d8 at Level 7, 1d10 at Level 10, and 1d12 at Level 15.

Iron Chin

Also starting at Level 3, while you are not wearing armor and not wielding a shield, your Armor Class becomes 12 + your Constitution Modifier.

Moxie Fueled Fists

At Level 7, that fighting spirit you built with your own grit makes your unarmed strikes count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks.

Fancy Footwork

At Level 10, you light on your feet, and you know how to maneuver around your foes. You gain proficiency with Dexterity Saving Throws, and your speed increases by 10 feet.

Haymaker

At Level 15, when you begin your attack action, before you make any attack rolls involving unarmed strikes that don't already have disadvantage, you can declare that you are throwing wild haymakers. If you do, all attacks are rolled with disadvantage until the end of this turn. However, any attacks that hit deal the maximum value of your Fistcuff die as damage without rolling.

Swinging wild haymakers can use up your energy. So you can only use this feature a number of times equal to your proficiency bonus. You recover all expended uses of this feature after you finish a short or long rest.

Peak Physical Condition

At Level 18, you achieve top fighting form, and your muscles are like solid rock. You gain resistance to bludgeoning, piercing, and slashing damage.