The mechanics of this quest are basically a slightly tweaked version of Burn Legend, as found in the Exalted sourcebook Shards of the Exalted Dream.
Attributes
Martial artists have three attributes: Strength, Dexterity and Stamina. Their uses should be self-explanatory. Most martial artists have ratings from 1 to 5. Attributes are used in combat to help land techniques and determine and resist damage from successfully executed techniques.
Techniques
The attacks a martial artist uses in combat. Like attributes, techniques are usually rated from 1 to 5. The higher the rating, the higher the chances of the technique being successful.
Ki & Willpower
All martial artists possess a pool of five points of ki, and five points of Willpower. Ki is used to fuel powerful martial arts techniques, while Willpower may be used to execute legendary techniques, as well as to reach deep and attempt to turn the tide of battle.
Ki is regained during battle through the use of certain (primarily Defensive) techniques; these can never grant the martial artist more than five ki at once, however. Martial artists begin all battles with five full points of ki.
Willpower, on the other hand, is only regained by winning battles. Victory in battle (defined as defeating one's opponents, or successfully achieving an objective despite martial opposition) restores two points of Willpower.
Combat
Combat is round-based. You all vote on a technique, then the winning technique is matched against whatever the opponent uses.
If combat takes too long with this system or a lot of people are worried it might, I might change it to have you vote on a certain "strategy." Like, for example, choosing to fight aggressively, defensively, take advantage of superior Dexterity, etc.
Clever write-ins to do things like use the terrain to your advantage, psych out/manipulate your opponent, or use a technique in a creative way can provide bonuses as relevant.
Priority Resolve
Each technique falls into one of six types: Strike, Aerial, Projectile, Rush, Grapple, or Defense. When two fighters deploy their techniques against one another, one of three results can occur: defeat, Clash, or Hit Trade.
Victorious Technique
Almost all techniques have one category of techniques they absolutely defeat. Basic Technique: Basic Strike, for example, automatically beats Aerial techniques. Thus, if two fighters attack one another, and one plays Basic Strike (which defeats Aerial techniques) while the other plays Aerial Strike (which defeats Projectiles), the fighter using the Basic Strike will automatically win, and proceeds to roll damage.
Priority Clash
If neither technique cleanly defeats the other, then the victory is down to which fighter executed their attack faster, or better. Both fighters make a Clash roll, rolling a number of d10s determined by the technique they have played; each die that lands on a 7 or higher counts as a success. The fighter who accumulates a higher number of successes wins, and his technique defeats his opponent's.
Hit Trade
There are two circumstances in which neither technique cleanly loses: when both techniques automatically defeat the move they are facing, or when players accumulate equal successes in a Clash. In this case, both techniques succeed, generally meaning that both characters inflict damage on one another.
A technique which Hit Trades is considered Victorious.
Damage & Defeat
When a technique has been successfully executed, its listed damage value is rolled as a dice pool. Successes from Clash rolls are not added to this roll, and 10s count as two successes rather than one. A damaging technique automatically removes one health point from the target, plus one additional health point per success.
Each damaging technique also lists a minimum damage. The calculation listed in the technique's damage section cannot produce a dice pool lower than this value.
Health & Health Stocks
Fighters possess seven health points and five Health Stocks. When a fighter's health points are fully depleted, she must roll her current Health Stocks as a dice pool. If no successes are gained on this roll, the fighter is rendered unconscious, and loses the battle. If at least one success is rolled, then one Health Stock vanishes, and the character restores her health points to full, and may continue to fight.
Damage in excess of current health points 'rolls over' when a Health Stock vanishes. Thus, a character with three health points who suffers four damage and succeeds in her roll to stay conscious would immediately lose one health after her points replenish themselves.
Refinements
In addition to their base effects, some techniques possess refinements—special executions that enhance the technique in some way. Refinements have a minimum dot rating requirement which the technique must meet before they can be purchased, and a listed experience point cost. Additionally, some refinements are marked as exclusive. A martial artist may only learn one exclusive refinement per technique.
Movement & Range
There are two distances fighters can occupy in relation to each other: near and distant. Movement and range are handled by a technique's two Range values. These describe, respectively, the range of an opponent the move can be used against, and how the technique moves the martial artist.
The first value may be Close or Mid. A Close attack may only strike a near opponent. A Mid attack may strike a near or distant opponent. A Close technique used against an opponent who remains at a distance automatically fails.
The second value may be Advance, Still, or Back. A Still technique does not move the martial artist. An Advance technique moves the martial artist from a distance to be near her target. A Back technique moves the martial artist from near her opponent out to a distance. An Advance or Back technique used by a martial artist who is already (respectively) near or distant from her opponent simply leaves them at that range.
A martial artist using an Advance or Back technique to change ranges is considered to occupy both near and distant ranges during the instant she attempts to move. Thus, it is sometimes wise to play a Close technique even against a distant opponent, in the hopes that she will attempt an Advance technique, bringing herself into range.
A martial artist who attempts an Advance or Back technique that fails is left at the range he formerly occupied at the end of the round.
Multiple Opponents
Honorable combat in the martial arts world is a contest of strength and skill between two fighters. Alas, not all fighters are honorable, and sometimes martial arts battles involve uneven numbers and groups of foes.
When a martial artist is targeted by two or more opponents at the same time, the technique she plays acts as a defense which determines whether or not her attackers can harm her.
For example, Goku is sparring with both Krillin and Yamcha. Goku attacks Krillin with a Basic Strike. Krillin uses an Aerial Strike, while Yamcha uses a Basic Strike of his own.
Goku's Basic Strike cleanly defeats Krillin's Aerial Strike. Yamcha's Basic Strike Clashes with Goku's, however, so the two roll their Clash pools. If Goku gains more successes, he will defeat Yamcha's technique and suffer no damage. However, because his Basic Strike was not aimed at Yamcha, he does not deal any damage to him. If Yamcha gains more successes, he will damage Goku. The defender of multiple attacks makes only a single Clash roll to determine his defense from all incoming techniques.
A fighter may be attacked by a maximum of three total opponents in a round.
Stagger
Even the sturdiest of martial artists cannot withstand long strings of unanswered blows without becoming disoriented. When a martial artist suffers damage from three techniques in a row, then the next round, when her selected technique is revealed, she must roll to resist Stagger. This is a Stamina roll against difficulty 2 (that is, they must roll at least 2 successes to pass). If the roll is successful, her technique plays out normally. If it fails, she is Staggered, and her technique automatically fails.
Sudden Comebacks are also possible at this point. If the martial artist successfully resists Stagger and lands a Victorious Technique against her opponent, the opponent must check to resist Stagger in the next round.
Reversal
Once per battle, a martial artist may reach deep into her burning spirit to give herself a second chance. Attempting a Reversal costs one point of Willpower.
In any round, you have the option to add the following to your vote:
-[X] Reversal
If this vote passes, then if your technique would automatically be defeated by your opponent's, you can change it to one that will Clash instead. If this doesn't happen, then your Reversal is not spent and you can use it again later.
Overdrive Techniques
Finally, some martial artists possess a ten-point Overdrive meter. One point is placed into the meter every time the martial artist successfully inflicts damage on her opponent.
Once the meter contains ten points, the martial artist may spend one Willpower point and all ten of her Overdrive points to use an Overdrive Technique.
Overdrive Techniques are powerful attacks, often unique to the martial artist using them, which are used to end fights. In addition to inflicting their listed damage or other effects, a successful Overdrive Technique automatically removes one Health Stock from the opponent, and forces the opponent to immediately roll to remain conscious after this Stock's removal. Because they tend to be very damaging attacks, an Overdrive Technique may even force an opponent to roll to remain conscious twice, by removing a Health Stock and then immediately depleting the target's health points!
A martial artist may only know a single Overdrive Technique.
Firearms
Effective though they may be for settling mundane conflicts, guns have little standing in the martial arts world, where they are an indication of cowardice or lack of confidence in the strength of one's fists. Thus, guns are the tools of thugs and lackeys, or martial artists who have utterly lost their nerve.
Firearms attacks are treated as Projectiles which defeat nothing, roll Dexterity alone for Clashes, and inflict (5 – Dexterity, min 1) damage. A character wielding a gun may use only his gun and Basic Techniques so long as he holds the firearm and for two turns after discarding or losing it. Suffering a single damaging attack both disarms him and automatically results in the loss of a Health Stock (or all Health in the case of an Extra).
Character Advancement
At the end of each "episode," you gain 2 XP, although in some cases you may earn 4 or even 6 XP instead, and certain training arcs will provide very large amounts of XP. Anything bought with XP may require in-story justification or be vetoed (you cannot, for instance, spend XP to learn the Kamehameha if you've never even heard of it or seen it performed).
Basic Technique: 2 XP
Martial Arts Technique: 3 XP
New Martial Arts Technique: 4 XP
Attribute: 8 XP (10 XP if increasing past 5 dots)
XP Debt
When you don't have enough XP to purchase a martial arts style or technique (and only a martial arts style or technique), you can choose to enter XP Debt. Your XP will go in the negative values and you will learn the style or technique, but you cannot spend XP on anything until your XP total enters the positive numbers again.
Perks/Drawbacks
Characters may have certain Perks and Drawbacks associated with them that affect them in various ways, both in and out of combat. Perks and Drawbacks can only be gained, lost or changed through roleplaying, and some not even then.
Non-Combat
Everything other than combat is decided entirely through roleplaying.