You have trained in the art and sport of boxing. Be it for wealth, glory, or for the love of the sport, you know how to please the crowd and control the ring. Boxers hone their closed fists to become weapons of great danger, abandoning all forms of traditional weaponry in favor of engaging in bouts of pure physical prowess. While the rogue may sneak up on their foe to get in a dirty hit, and the spellcasters may use their spells to strike their opponent down from a distance, Way of the Boxer monks pummel their opponent with superior technique, stronger willpower, and unwavering bravery.

Breaking the Mold

When you choose this tradition at 3rd you may choose to use your Constitution instead of your Dexterity for your Unarmored Defense feature.

In addition, you give up the use of any traditional weaponry that the use of doesn't count as punching. (Weapons such as gauntlets, knuckle dusters, and so on are fine)
Wielding a weapon stops you from using your Way of the Boxer features, even if the weapons would count as monk weapons.

Bob and Weave

At 3rd level, you learn how to twist and move your head and body in response to attacks from your foes, evading their strikes to the best of your ability. When you get this feature, you may spend a Ki point to use the Dodge action in place of one of their unarmed attacks.

Boxing Style

At 6th level, you begin to focus on a certain style of boxing that suits you and your body the best. Your chosen style of boxing will give you an edge in battle which suits your way of fighting the best.

Brawler

As a Brawler, you have learned to ignore any fear of pain, moving in close to your opponent and exchanging brutal, bone-shattering blows with them as if it was nothing.
Sacrificing speed for power, you are given the option to use your entire attack action for one huge swing. Landing this blow will cause devastating damage to the target, dealing 3 of your unarmed attack dice worth of damage. However, missing this attack will cause all attacks on you to have advantage until the start of your next turn.

Outboxer

As an Outboxer, you have learned to dance around the ring with your skillful footwork, always maintaining the distance between you and your opponent with your skillful counters and jabs.
If an opponent attacks you with a melee weapon attack within your reach and misses, you may use your reaction to throw a counter at them, dealing your normal unarmed attack damage + their attack modifier. After landing or missing this counter, you may spend a Ki point to move up to half your movement without triggering an attack of opportunity from that opponent.

Swarmer

As a Swarmer, you move into your opponent's comfort zone with speed and tenacity, pummeling them with rapid punches that leave your opponent with no chance to fight back.
As a bonus action, you may spend 3 Ki points to start swarming your opponent. You may make as many unarmed attacks against a single target as you please until you miss an attack, which ends the swarm. These attacks deal 1d4+your damage modifier worth of damage.

Unorthodox

As an Unorthodox boxer, you move to your own rhythm, controlling the flow of the fight by making sure that your opponent has no idea what you will do next.
By confusing your opponent with your unique rhythm and movements, you may spend a Ki point to throw a feint with one of your unarmed attacks. By using a feint, you grant your next unarmed attack advantage and that attack will crit on both a 19 and a 20.

The Ring

At 11th level, the inside of the ring has become home to you and you gain the ability to project one through your willpower.

You may spend 3 Ki points to create a 20 ft square as an action. This 20 ft square is surrounded by the ropes of a boxing ring which prevents the fighters inside from being forcibly moved out of the ring. When you create this effect, you must choose an opponent that is within the area of the square. You must also be within said area. All others aside from you and your selected opponent are knocked out from the area of the ring. Entering the ring is impossible and attack rolls aimed at the fighters done from outside the ring are done with disadvantage. The ring stays there until one of the fighters is knocked out, leaves the ring, or 3 minutes pass.

The fighters gain confidence from their allies that choose to cheer them on. Allies of the fighters that are within 5 feet of the ring are considered to be ringside. The fighters gain +2 to their attack rolls and +1 to their attack damage for each ally that is ringside (To a maximum of 3)

Though entering the ring is impossible, a fighter may exit the ring at any time. This however brings great embarrassment to the fighter for running away, stunning them for a number of rounds equal to the number of ringside allies they have, as they freeze at the sight of their allies' judging gazes.

Last Stand

At 17th level, you're determined to win no matter what, even at the risk of your life.

If you are within the area of The Ring and are dropped to 0 hp, you are able to keep fighting up to a number of rounds equal to your wisdom modifier. While you are in this state, you do not need to spend Ki points to use Flurry of blows or any other class feature granted by the Way of the Boxer. If you manage to knock your chosen opponent unconscious or they leave the ring, you are returned to 1 hp. If the chosen opponent decides to stay in the ring and manages to live through your last stand, then you fall unconscious with 1 failed death saving throw.