Expanded effects for Luck

[lukep]

Currently, Luck affects saves, accuracy, defense, crit rate, and a couple of other small things. I think that this could be expanded to include a new effect, without becoming OP, specifically, a chance based on luck to reroll hits and save attempts.

One way of doing this would be to take (attacker luck - defender luck) * 2 and use that as a percent chance to reroll successes or failures. For example, a halfling with Lucky day (95 luck) fighting an orc (50 luck) would have a 90% chance of rerolling every time he would miss, or that the orc would hit.

[SageAcrin]

Only one reroll per attack, I'd hope.

I'd rather see it do something like give a projectile deflection rate, or a chance to mitigate attacks that do hit by a certain amount of damage, or give you a chance to not die from fatal hits, something like that.

But I'd have no problem with the reroll idea. 90% strikes me as a bit high, I'd rather see that be (Luck Difference) chance of a reroll, so you'd get 45% in the target example.

[lukep]

Yes, one reroll per attack (hmm, maybe if the chance is above 100%, then a chance of two rerolls?). I thought about having it be less (eg. 45%), but that would be so weak as to be almost negligible. A 50% chance to reroll is strictly worse than +5 to the save/power, while a 100% chance to reroll is worse than a +10. Also keep in mind that Luck is relatively rare, outside of one Prodigy.

[Doctornull]

This applies to monsters too, right?

So a Cursed using one of his tier-4 stance talents (comes with a -3 Luck penalty), or using the Cursed Equipment tree, will be taking a lot more hits?

[lukep]

A few more, yes.

-3 luck would mean you reroll 6% of your successes, so a 50% chance to be hit increases to a 53% chance.

[Doctornull]

So expressed in terms of expected damage, if both you and your foe have a 50% chance to hit, -3 luck would be -3% resist all and -3% damage all.

That seems kinda hefty.

I dunno. Maybe Luck can do something less related to combat, so taking Luck boosts instead of a combat buff is a trade-off? Maybe something like... roll Luck to see if you recover one of your opponent's Inscriptions when it dies.

[SageAcrin]

Yes, one reroll per attack (hmm, maybe if the chance is above 100%, then a chance of two rerolls?). I thought about having it be less (eg. 45%), but that would be so weak as to be almost negligible. A 50% chance to reroll is strictly worse than +5 to the save/power, while a 100% chance to reroll is worse than a +10. Also keep in mind that Luck is relatively rare, outside of one Prodigy.

Oh, I was assuming you meant immunity checks as well, but you don't state that.

I guess that's accurate, then.

[lukep]

So expressed in terms of expected damage, if both you and your foe have a 50% chance to hit, -3 luck would be -3% resist all and -3% damage all.

That seems kinda hefty.

I dunno. Maybe Luck can do something less related to combat, so taking Luck boosts instead of a combat buff is a trade-off? Maybe something like... roll Luck to see if you recover one of your opponent's Inscriptions when it dies.

It's about half as effective as +1 accuracy +1 defense. Also, I wouldn't like it to have a permanent effect like it would have for item generation.

Oh, I was assuming you meant immunity checks as well, but you don't state that.

I hadn't thought of immunity checks, but I don't think it would be too extreme to include then either. If it checked against 50% immunity, +50 luck would swing it 25 percentage points either way (effectively 25% or 75%), while +5 would swing it 2.5 percentage points (effectively 47.5% or 52.5%).

[HousePet]

Not keen, Luck already affects all attack/defence rolls. Double dipping is silly.

Would be an interesting effect for Revisionist History though.

How about Luck giving you a chance to take half damage from spell/mind attacks?
Or even a chance to take half damage when such damage would kill you?

[SageAcrin]

Yeah, I like the rerolls for Revisionist History idea better, too.

That really fits it.

[Doctornull]

Would be an interesting effect for Revisionist History though.

Nice. With a moderate cooldown (3-5 turns) so it's not happening too many times per combat. Having a visible cooldown would also make this effect of Luck more visible than the usual effects, which is nice... you can see what that Amulet of Serendipity is doing for you.

Or even a chance to take half damage when such damage would kill you?

Hmm. I like this idea, but it's not hard to get 100 Luck, so it would have to also have a cooldown or otherwise not be an implementation of Zeno's half-damage paradox.

Alternately, you could "luckily" activate a Shield Rune or Heroism Infusion just before you would have taken lethal damage, which implicitly gives you an effect cooldown: when you have no available applicable Runes or Infusions, you die (no save).

This might make Lucky Day builds favor a somewhat different Inscription layout from the usual.

[HousePet]

Zeno's half damage paradox only occurs if you assume nothing ever deals more damage than it needs to, to kill.
I'm pretty sure ToME is quite happy to overkill.

[Hachem_Muche]

I think it would be simpler (and safer) to let luck only affect the lucky/unlucky character, making it mostly a defensive stat with very limited offensive potential. Besides revisionist history, things like saving throws, equilibrium/paradox checks, teleport fizzles, friendly fire chances, etc could also be affected. Basically, certain defensive things that you have a chance to fail, you have smaller/greater chance to fail with good/bad luck.

The formula would be something like:

reduced chance to fail = chance to fail * (1-bonus luck/(bonus luck +50))

for a lucky character or

reduced chance to succeed = chance to succeed * (1-luck penalty/(luck penalty + 50))

for an unlucky character, so that luck can help or hurt you, but can never guarantee anything one way or the other.

[HousePet]

Luck already affects saving throws and friendly fire.
Teleport fizzle isn't chance based.
Not sure that adding small modifiers to existing small chances is worth doing.

[Hachem_Muche]

I guess it's not applied consistently. Friendly fire from alchemist bombs are not affected by luck, and targeted phase door has a flat 35% fizzle rate for targets outside of LOS.

Small modifiers can have a big effect in certain places. The luck effect on Unseen Actions can make a big difference in it's usefullness, for example.