We can talk about technique and conditioning later, but if you want to pursue the art of pugilism it's best to start with what's really important: picking something totally sick to tattoo on your knuckles.

Possible Keystones 1. Gleaming brass knuckles.
2. Leather punching bag.
3. Classic kung-fu flick on VHS, mint condition.
4. Athletic mouthguard.
5. Booklet titled “Guided Meditations on Violence”.
6. Steel-toed shoes, surprisingly light.

This is a weapon and subject to universal weapon rules.

Brawler Kicks and punches.
caret-right Flurry Multiple fast attacks.
caret-right Lockup Interfere with their attacks.
caret-right Smackup Failure is only lesser success.
caret-right Walter Grab one and beat it out of them.
caret-right Whirlwind Attack everything nearby.

Brawler

Active Combat plus-circleKnuckle Sandwich: As an action, you may make a Melee attack against any target within 1 meter.

plus-circleConditions: When the trigger die is 10+, this weapon inflicts its wielder's choice of the Choking, Dizzy, or Nauseous conditions to its target.

plus-circleSkullduggery: This weapon can be used to backstab (+2 damage to targets that cannot see you) and assassinate (instantly kill targets of equal or lower level who weren't expecting an attack).

plus-circleSemi-Aquatic: The weapon has a failure chance of 6 when used underwater instead of such use being impossible.
Condition Explanation
noose Choking minus-circle Lose 1 Energy at the end of each round. If no Energy remains, lose Flesh instead. Successfully throwing off the condition prevents damage for that round.

minus-circle Making a recovery action no longer restores 1 Energy (but still allows a check to remove a condition as normal).
ringing-bell Dizzy minus-circle Every time a movement action is taken, lose 1 Energy.

minus-circle Cannot dash (travel further in exchange for Energy) during a movement action.

plus-circle Movement made for free (without spending any actions) is unaffected.
turd Nauseous minus-circle All weapon attacks cost 1 Energy in addition to any normal costs they may have.

minus-circle Cannot double attack during a round.

plus-circle Weapon attacks made for free (without spending any actions) are unaffected.

Flurry

Active Combat plus-circleORA ORA ORA: You can choose to attack rapidly, hitting twice as a single action. Both attacks are directed at the same target. Roll separate attack trigger dice for each strike.

plus-circleTwo Hits, One Attack: Using Flurry counts as only a single attack, not two. If you've already Flurried in a round it does not count as a double attack unless your second action is also a weapon attack.

minus-circleAccuracy Drop: Both attacks in a Flurry have a special failure chance of 3.

Lockup

Enhancement plus-circleArmbar: Your strikes severely interfere with your target's ability to fight back. Any creature you successfully damage with this weapon has a failure chance of 3 with all weapon attacks.

minus-circleWithdraw and Recover: As soon as an affected enemy gets out of your reach (usually this means moving away so they're no longer adjacent to you), the effect ends automatically. Note that this is generally impossible for any creature that you've inflicted the Grabbed condition to.

Smackup

Enhancement plus-circleQuad Dela Ron Sha: When your attacks with this weapon fail for any reason, you treat the attack as landing but deal half damage (round fractions down) instead of doing nothing. This half damage is then reduced by the target's Melee combat rating as normal.

minus-circleNo Bonuses: An attack that failed cannot inflict any additional conditions or extra effects that depend on having a high trigger die result, no matter what it actually is.

Walter

Enhancement plus-circleGreat Plan, Man: You deal +2 damage against targets that you or an ally has inflicted the Grabbed condition to.

Whirlwind

Active Combat plus-circleMultiattack: You can choose to hit every creature adjacent to you with your attacks, not just only one. This counts as a single attack no matter how many targets you hit.

plus-circleTasmanian Combo: If you also have the Flurry ability from this archetype, you can combine it with this one to hit everything around you twice as a single action (with a failure chance of 3 on each hit).

minus-circleWild Swing: Whirlwind attacks can hit allies as well as enemies.

minus-circleExertion: Performing a whirlwind attack costs a point of Energy in addition to an action.