Path of the Pugilist

You have made your name primarily as a gladiator, but a champion fighter isn't just show. Your fists are like steel, and you can read an enemy like a book, so weapons are a hindrance to your skill in most cases. You never like to pass up a good fight, and you prefer to set ground rules for your fights---a carryover from your past as an entertainer. 

Fists of Power

At 3rd level, your fists are just as effective as weapons for you. You can roll a d4 in place of the normal damage of your unarmed strike. This number changes as you gain levels in this class: d6 at level 7, and d8 at level 14. 
In addition, when you use the Attack action with an unarmed strike, you can make one more unarmed strike as a bonus action.

Champion's Focus

Beginning at 6th level, you've trained your skill to dodge enemy attacks. If there is only one enemy within 5 feet of you and you aren using a shield or weapon, you gain 2 AC against any melee attack made by that enemy against you.

Duck and Strike

Beginning at 10th level, you learn to exploit blind spots in your enemy's defenses. If there is only one enemy within 5 feet of you and it misses you with a melee attack, you can use your reaction to make an unarmed melee attack against them.

Knockout Blow

Beginning at 14th level, you know how to throw a punch that can down an enemy in one blow. You can choose to give up any extra attack and your bonus action attack that you normally have to make one single powerful uppercut. If this punch hits, it is automatically a critical hit, and the enemy is stunned until the end of your next turn.