Update: Lethal Fighters, 2.0

 Here's an update to my recent ideas about flashy, risky, lethal maneuvers for Fighters. I got some great feedback (here, and on Reddit/Discord). Although I haven't agreed with or implemented all the feedback, the conversation has really helped me hone this further, and some feedback has led to significant tweaks.

Among the most notable changes: decisive maneuver attempts/gambits still risk serious consequences, but when triggered such consequences now involve HP loss down to set thresholds (instead of getting narratively maimed or killed, and trying to block that with armor or abstract points). Also, I have decided (for now...) to decouple such gambits from the normal to-hit roll procedure. In the initial version, I suggested that one could require two normal to-hit rolls and base the full/partial/no success results off that. As one reader pointed out, doing so makes such gambits significantly less appealing for low-level fighters who don't yet have attack bonuses and magic weapons equal to common, mid-range Armor Classes. As you'll see, I'm now proposing a more truly system-agnostic flat roll, still based on the PC's skill/training relative to the target's (measured as level vs. HD). But there are no longer any bonuses added to this flat d20 roll. This means that all Fighters of a certain level have the same chance to pull off the same maneuver against the same opponent. That might seem odd or limiting, but I'll counter that this is not out of place in a classic or OSR game. In Old School Essentials, for example, all Clerics of the same level have the same chance to turn undead; all Wizards of the same level know the same number of spells; and all Fighters of the same level have the same chance to pass a Saving Throw against Breath Attacks or other, non-magical hazards. The closer you get to OD&D or B/X, the less Ability Scores really serve to differentiate among different PCs. I've harnessed that, letting individual player creativity and daring shape which Fighters of the same level feel better suited to attempting dangerous stunts. 

A flat roll also makes this hack compatible with a variety of systems, no matter which bonuses they do or don't use for their normal hit rolls. Slap this atop Knave for a Fighter class, or plug this into OSE to enliven the watching-paint-dry B/X Fighter. Of course, this should change the tempo and feel of combat - and this still requires playtesting. But I think this is getting closer to something coherent enough to test.

 Here, then, is my "Lethal Fighter, Quadratic Wizard" 2.0.

ATTACKS AND STUNTS FOR ALL CHARACTERS

Your game's normal combat to-hit rolls remain in effect. Foes still drop at 0 hp. Often, Fighters will want to stick with such normal attacks, which risk nothing on a miss other than a wasted action. 

Alternately, any character may use their combat action to attempt a combat stunt that does NOT directly deal damage. Use your system's regular procedure for task resolution. Examples: trip an enemy to knock them prone, parkour behind a foe to set up an advantageous strike, etc. Often, such stunts will incur advantage to follow-up attacks, or impose disadvantage on the foe's attacks, until the foe can act to change the situation. Stunt may be attempted against any foe, and in any situation, so long as the GM agrees that the attempt makes contextual sense. 

With the GM's permission, stunts may lead indirectly to damage against foes - for example, tripping an orc atop a castle rampart might cause it to fall to its death ("I didn't kill him. The fall killed him."). GMs may allow the affected foe a relevant Saving Throw to avoid such a fate. 

A foe discombobulated by a Stunt counts as STAGGERED. Enemies (not PCs) also count as STAGGERED when they are at 1/2 their max hit points, or lower. This tag becomes relevant for Fighters...

THE LETHAL FIGHTER

Fighters also have access to additional maneuvers and related abilities. 

Fighters are trained predators, swift to assess subtle signs of violent skill - or vulnerability. A Fighter may spend a combat action to determine whether any single foe in melee is currently at 1/2 hp or lower (and thus STAGGERED), and whether that foe's HD are much higher, higher, equal, lower, or much lower than their own level [NOTE: per the teachings of St. McDowall, I'm tempted to just give Fighters this information for free, rather than requiring an action].

Fighters (and only Fighters) may attempt Maiming Strikes and Killing Blows. These represent risky but skilled attempts to exploit momentary openings to change or even end a fight. If a Fighter's speed and skill beat their opponent's, such gambits can be very useful - but they require closing to dangerously intimate range, making the Fighter highly vulnerable should their maneuver fail. 

Accordingly, Maiming Strikes and Killing Blows can only be attempted in Melee - not with Ranged Attacks. 

MAIMING STRIKES are maneuvers in close combat that cause direct damage or ability loss, beyond simple HP loss (to inflict simple HP loss, make a normal to-hit roll as usual, which risks nothing but a wasted action on a miss). A Maiming Strike seeks to impose a lasting debility on a foe or to deny a specific ability to the foe. It is similar to a "called shot"; it is similar, too, to a combat stunt, but once affected a foe can not simply 'snap out of it' by standing back up, wiping sand from their eyes, etc.

Select Examples:

• Slicing an ogre's wrist-tendons, granting Boon/Advantage to further attacks against it and imposing Bane/Disadvantage on the ogre's own attacks.
• Shearing off a giant scorpion's tail stinger, so that it loses its venemous attack option.
• Stabbing out the eye of a creature with a gaze attack. 
• Blinding a cyclops, so that its further attacks count as vs. invisible targets. 
• Crushing an opponent's groin, inflicting searing pain that hinders their further actions with Disadvantage. 

In each case, the maneuver differs from a regular combat attack because it has the potential to change the target's combat abilities, and/or impose mechanical penalties, that remain in effect for the rest of the fight. A Maimed foe automatically counts as Staggered for the remainder of the fight. 

KILLING BLOWS use the same idea, but they directly kill an opponent. Chop off the ogre's head. Slice the wicked Sir Rodney from collar to hip-bone. Pierce the dragon's underside and drive your spear into its heart. 

But such useful strikes are risky, and are limited by a Fighter's skill relative to their foe's.

FOE CATEGORIES

When fighting foes with:

Much higher HD (6+ HD higher than level): the Fighter may NOT attempt Maiming Strikes or Killing Blows against this target. 

Higher HD (2-5 HD higher than level): the Fighter may attempt a Maiming Strike against a Staggered Target, or a Killing Blow against an already Maimed target. 

Equal HD (+/- 1 HD): the Fighter may attempt a Maiming Strike. Against a target that is already Staggered or Maimed, the Fighter may attempt a Killing Blow. 

Lower HD than your level: the Fighter may attempt a Maiming Strike or Killing Blow. 

Much lower HD (half your level or lower): the Fighter may attempt a Maiming Strike or Killing Blow. A successful Killing Blow affects multiple eligible targets up to the Fighter's level (a lvl 3 Fighter may kill up to three 1-HD targets, a lvl 6 Fighter may slaughter up to 6 3-HD targets, etc.). To attempt such a maneuver against multiple targets, use the "Lower HD" rather than "Much Lower HD" TN. 

THE ROLL TO EXECUTE THESE MANEUVERS (PUN INTENDED)

To attempt a Maiming Strike or Killing Blow, run your idea past the GM, who will confirm whether the proposed maneuver would work in the current context and as envisioned by the player. Make sure both GM and player share an understanding of the possible outcomes. 

Then, the Fighter's player rolls 2d20, and checks whether they rolled 0, 1, or 2 successes vs these Target Numbers (no modifiers are added to the rolls):

Higher foe    TN 14+

Equal foe    TN 11+

Lower foe    TN 8+ including multiple Much Lower foes)

Much Lower foe     TN 5+ (for a single foe)

If a foe is very well-armored (ascending AC 17+), treat their TN as one category higher. If a foe is very poorly armored (ascending AC 12-), treat their TN as one category lower. If a foe is Staggered (and/or already Maimed), treat its TN as one category lower. 

RESULTS

2 Successes: you accomplished your intended Maiming Strike or Killing Blow! Also, inflict your normal weapon damage agains the target's HP. 

1 Success: you accomplished your intended maneuver, AND you inflict your normal weapon damage agains the target's HP -- but at great cost. If you achieved a Maiming Strike, you also take damage that drops your hit points to the next-lower threshold (Full HP, Half HP, Quarter HP, 0 HP). If you achieved a Killing Blow, you take damage that drops you by TWO HP thresholds. (For example, a Fighter at about 60% of their max HP would fall to 1/2 HP (Maiming Strike) or 1/4 HP (Killing Blow). Writing down these threshold levels on the character sheet will speed up play. 

0 Successes: your intended maneuver fails, and you pay a great cost. Suffer damage to HP as described above. 

Ouch! These maneuvers are risky. But Fighters have a limited way to mitigate that risk. Once per day/overnight rest, they may narrate how their armor, cat-like reflexes, etc., saved them from one consequence (this fully absorbs the consequence from a Maiming Strike, but still leaves one "hp step" inflicted after a failed Killing Blow). If a GM allows players to "sunder" shields or helms from their inventory to ignore an attack's damage, a Fighter may also sunder their shield or helm to ignore one consequence-step from a bad maneuver -- but only once per day. 

EXPECTED IMPACT ON THE FLOW OF COMBAT

As noted above, these still require playtesting, but I think they're now in a shape to allow it. I think what that will reveal is that this retains the value of all players' normal attacks - they can still kill off foes by dropping them to 0 hp. However, non-Fighter attacks are now helpful because they set up the Fighter to be able to pull off a Maiming/Killing attack more easily against a Staggered target at 1/2 hp. But the risk of losing a lot of HP at once should limit how often Fighters try these moves. I'm hoping this leads to 'signature moments' when Fighters really shine ... or really groan when the move goes wrong. Adding a simple but regular dimension of risk-reward analysis should enliven the Fighter, giving the player a sense of reading the flow of battle and always assessing whether or not to attempt a quick, finishing blow that ends a potentially dangerous threat. This also lets creative players narrate debilitating attacks that actually feel more consequential than just dropping HP off a monster. 

A pair of Fighters can work together -- if the dice cooperate -- to stagger, then maim, or maim, then kill, an opponent. Teams can experiment to find their own rhythms. Of course, different encounters will call for entirely new approaches.

Thanks for reading, and for any further feedback.