Deadly combat systems

Modos RPG: you get three actions per round. If you don't use them for defense, well, that's on you. And gaining hit points each level is optional, not mandatory.

Let's try a specific scenario to try and add a bit of quantification to this question:

Assume a starting player character designed for combat uses their favorite weapon to attack an exact copy of themselves using a readily available weapon at preferred range, and that both are aware of each other. What is the chance that their target dies from one hit?

For Call of Cthulhu, I would expect a soldier to have a shooting skill of 50-75%, so let's say the middle- 62%. They might have a dodge in the range 25-45%, so let's say 35%. Doing the math that gives them a 40% chance of hitting their opponent. A shotgun is a common weapon in the most common CoC era, the 1920s, and does 4d6 damage at close range. 12 hit points is pretty typical, so per the rules, if 4d6 rolls 12 or more the target is instantly dead. This is a 76% chance, for a total of 31% chance of instant death. So -- for this measure, CoC has a deadliness level of 31%

Any challengers?

Classic RuneQuest: "Oh, look, another limb is off."

Blades in the Dark. If the GM deems that an opponent outclasses a PC enough, they just say, "You're no match for them. They quickly get through your guard and stab you in the neck. Take level 4 harm (i.e., dead). If your roll resistance you can lessen it but not avoid it".

Cortex Prime. In a game using complications, a high stakes roll results in the character being taken out unless they pay a plot point and ake a complication instead. The nature of the take it is up to the attacker, and can be "dead".

GrahamWills said:

Let's try a specific scenario to try and add a bit of quantification to this question:

Assume a starting player character designed for combat uses their favorite weapon to attack an exact copy of themselves using a readily available weapon at preferred range, and that both are aware of each other. What is the chance that their target dies from one hit?

For Call of Cthulhu, I would expect a soldier to have a shooting skill of 50-75%, so let's say the middle- 62%. They might have a dodge in the range 25-45%, so let's say 35%. Doing the math that gives them a 40% chance of hitting their opponent. A shotgun is a common weapon in the most common CoC era, the 1920s, and does 4d6 damage at close range. 12 hit points is pretty typical, so per the rules, if 4d6 rolls 12 or more the target is instantly dead. This is a 76% chance, for a total of 31% chance of instant death. So -- for this measure, CoC has a deadliness level of 31%

Any challengers?

Click to expand...

A starting PC with over 40%??? Seems fishy to me. Then again, I last played CoC in the 80's, and my BRP experience is much later.

Palladium Fantasy, Soldier in plate, 80% chance of hit, but only 20% chance of doing damage to the PC. And that's about halved by the parry or dodge. HP will be probably in the 15 to 20 range, but the weapon's only doing 1d10 or so...
So we need a nat 20 to crit, and the parry needs a nat 20 to block, so 19/400 and 2d10 vs 16 HP... so that's 10%... for 19/4000 Now if goon got lucky on PE roll, that could be as low as 0%, because he's got up to 30 HP.

Classic Traveller: you can't optimize, since your choices are few. Assuming a typical 1 term army guy, he's got Rifle 1, and is in cloth armor. (WHich is the best he can afford). And back ally encounter range (short ... ~5m) And we'll assume A98765 stat profile, so he can soak 27 points of damage. (A=10, so A+9+8= 10+9+8). Needs a 9+ on 2d6+1 (I'm using the Snapshot table, as it's easier than using the Bk1 table, but it matches the odds. 10/36 odds of telling hit; that's 6d damage and it's first shot, so average damage is 21 to a single att, so pretty likely to exceed the best att - 6d6 > 10 is 99.65% according to anydice... so a bit more than 27% instagib. But that one-shot stop isn't of need a kill. If the marine desires, and isn't engaged otherwise, he goes and kills the guy with a second shot, but either way, first of the two to hit walks away at his choice, the other goes by amulance or bodybag at the first guy's choice.

MegaTraveller, like CT, choice is not a great factor in char gen...
THe exact odds are different tho - same situation. The first shot is routine (7+) on 2d6+(Dex/5)+skill, Autorifle is pen 3 at that range, and cloth is 5 AV... pen 3 < AV5/10, so no-pen result... damage 3 is divided by /10... Blunt trauma effect
So... on nat 5 (4/10) damage is halved. so 0.075, rounds down.
On nat 6, damage is .3 - rounds down.
On nat 7, damage is doubled for being 2 over the needed final 7 to hit, which makes the damage .6,. but adds a minimum of 1 point through.
On nat 9 (make by 4) base damage is 1.2, but with minimum up to 2.
You'd need a nat 13 to hit the ×8 min 3... but can't do that. (If you did, it would be 2.4 base, but the min 3 applies)
If he's sniping (and thus has extra time) a nat 9 is a hit by 8. with minimum raised to 3.
That three is NOT going to kill, nor even drop, his mirror, due to having 4/6 hits. (first 3 don't drop, 4th does, then 6 more needed to kill.
So, no chance of a non-special-circumstance one-shot kill.

TTNE is far less deadly.

Thinking on this some more...
L5R 5E duelist... fire ring 3, MA-Melee 3.
Success chances - needs two successes on 3 kept dice, with each strain marker also counting a success.
Potential to hit = infinite successes; if iterating a maximum of two explosions deep, that's a potential for 18s Max armor 6; 4 is normal for bushi, especially starting.
Black die success count in fire [0, 1, 0, 2, 1, 2*]= 6/6= expectation of 1 expected success
White [0,0,0,0,0,2,2,1,1,1,2*,1*]= 10/12. So we can expect 3 kept successes between success circles and strife flames.

When we count the explosions we add 1/6 and 1/36 to the black, for 7/6+1/36= 43/36 expectation., or 1 7/36.
White with explosions starts at 5/6, adds 5/36 and 5/216, so (180+30+5)/216= 215/216... So, we expect about 3 2/3 successes. On the correct Iajutsu, this means 5+2 damage, Not gonna be killing most of the time.

But there's an infinity there. It is unlikely for a starting PC to have maxed 12 fatigue, but it happens. So... on a low probability roll, it's possible to get up over 16 damage and zero out a PC on initial hit. I've seen it happen in duels.

(non-fire stance, those are B=[0,0,0,1,1,1*]=3/6 +3/36+3/216 and W=[0,0,0,0,0,1,1,1,1,1,1*,1*] =7/12+7/72+7/432 =252/432+42/432+7/432 =301/432 expected.

Now, in third ed...
a good starting character can be rolling 7k4 d10's, exploding, to hit... which Anydice can't calculate with the exploding.
TNTBH peaks for starting characters at about 35, so we'll use that. He's got a 10% chance of hitting himself if in full armor. If, however, it's a courtly duel... He's a 20 to be hit
10.10% and 95.3%, before explosions
Median damage is about 24, and the bushi is Earth 3... so about 4 lines gone. Still up. Peak is 30 without explosions. chance of instakill is about 5%... but exact calculations are a royal nightmare thanks to both XkY and exploding dice.

Both games have the potential to instakill their mirror, but it's not exactly likely. On the other hand....
A rank 4 Bayushi Saboteur in 3rd ed was able to get a rolled 10k10+55 to hit.... And Amaterasu is flat 10's for all rings, so was 75 TNTBH (extra 25 for kami in splendor)... He whacked Amaterasu-Kami from behind, with several free raises and a couple called raises to raise damage. So... in that campaign, Amaterasu was indeed replaced by a mortal, but it was a Bayushi Saburō. (Given the chance to guard the black scrolls, he decided to read them. «bleep»ing «bleep»-head Bayushi... wonderfully played in character for both PC and clan/school/family/setting.) He two-shotted her. KO strike 1, dead strike 2.

Now, in both editions, little nasty bakemono goblins are individually pretty wimpy... but they add together quite fast, and 3:1 odds are often dead PCs. (Done that in 5th ed more than once. But it wasn't exactly my fault - group was divided between "Let's fight" and "Take flight" - and the one "let's fight fought and died.

It's worth noting that PCs in 5th ed are not directly comparable to typical foes...

aramis erak said:

A starting PC with over 40%??? Seems fishy to me. Then again, I last played CoC in the 80's, and my BRP experience is much later.

Click to expand...

Hmmm. I don't think it's changed that much. You have 300 points to spend on skills, and your rifle skill starts at 25%. As a soldier it seems a bit over-restrictive to assume that I'd only put 15 points into my main skill. Even putting in 50 out of 300 into your main skill makes a lot of sense to me (which is the max most Keepers will allow for a starting character). Putting 37 out of 300 points into it seems pretty reasonable to me.

Can't recall where I found this or who was responsible for it, I'm afraid, but this handy chart compares the lethality of MSPE, Top Secret and Espionage (later revised as Danger International):

The 1983 Star Trek RPG was bonkers with energy weapons. A club would do 2d10 damage. A phaser 1 would do a flat 75. A sample character in the rulebook had 58 hit points total. Even if everyone was using stun settings, combat wouldn't last long. And if they weren't using stun settings? Oh well...

I remember an article where the designers noted this was intentional. They wanted a Star Trek RPG to be about finding solutions that didn't involve just shooting everything in sight. They designed combat to be so deadly so players would be forced to find alternative solutions. Gotta be one of the most deadly combat systems ever.

GrahamWills said:

Assume a starting player character designed for combat uses their favorite weapon to attack an exact copy of themselves using a readily available weapon at preferred range, and that both are aware of each other. What is the chance that their target dies from one hit?

Click to expand...

I'm not sure I'd call this a "deadliness level," but I'll bite.

Joe the soldier puts his good attribute score in Physical and his attribute point there: 13 health. His armorer provides a sword (d8, nothing fancy), breastplate to wear over his padded jack (brigandine, -2 Physical, d6), and small shield (+2 parry) - in addition to non-rules gear like leather bracers and a halfhelm. Joe's training is in Armed (combat) for 1 point, and his perk is probably not combat-related...let's not min-max here!

He charges into battle and attacks the first opponent he meets - someone with VERY familiar-looking gear. He doesn't hesitate though because his opponent is wearing a different tabard than his. Not-Joe raises his shield, planning on pushing Joe's sword-arm back far enough to create an opening...

Joe's attack is a d20+1 (if he's not feeling heroic enough to use a hero point); Not-Joe's defense is d20+2. Joe has a 45% chance to cause damage. His d8 sword averages 4.5 damage per attack, and Not-Joe's armor averages 3.5 protection per attack, or 1/11 of Not-Joe's health per attack, for about (9% x 45%) 4% of a kill per attack, or 1 kill per 25 attacks.

If Not-Joe wants a kill as much as Joe does, he can attack instead of defending. This raises Joe's damage chance to (almost) 100%, and Not-Joe's damage chance to (almost) 100% provided that Joe's attack doesn't disable Not-Joe prior to his counter-attack. Joe's damage percentage goes up to 9% in this case, as Not-Joe's goes from 0% to 9%, or 1 kill per 11 attacks.

So, how is this 0% Deadliness Level game "deadly?" Joe removes one damage point per day without a healer's help, so his damage sticks around. His defenses are limited to 3 per round, so if Not-Not-Joe shows up, Joe can't rely on additional parries - only his armor. There's no such thing as a "miss," so if Joe doesn't use an action or rolls poorly to parry an attack, he's taking a minimum of 1 point of damage. Finally, next level, Joe gains anywhere from 0 to 5 physical health, which is an "average" of 2.5 health per level. Tiny weapons (daggers, unarmed attacks) average this much damage with a d4, so good armor and some creativity are necessary for surviving against higher-level opponents, because increasing health alone is not (on average) a viable option.