Killer Stacking And Founder's Breastplate

So an interesting tech I don't see anyone talking about on paladin, is stacking Killer bonuses where applicable, for scenarios where they actually apply.

Assuming one uses a lua framework to automate gear swapping, and assuming the target is applicable, you can stack some fairly high killer chance on targets and then leverage Founder's Breastplate's "Augments "Killer" effects" for a lot of damage mitigation.

Killer Effects vs AoE
Its important to note that Killer Effects, when the proc, stop the entire move, and dont just mitigate it on yourself.

This means you spread the mitigation out to the entire party.

Not only that, but it will proc and mitigate non damaging moves too. The prime example being AoE debuff *** that makes your healer's work overtime. You will absolutely be the party's best friend if you multiple times proc a killer effect that negates some *** move a boss uses that inflicts a bunch of status ailments on all your DDs.

Content that actually cares about this
It's no secret though that a lot of content features bosses that don't even fit into any of the standard "killer" bins, so as a result all of this info below is useless for them.

Odyssey: All of the T3 and T4 bosses are in targetable families, especially Bumba which is a dragon and we can hit very high killer bonus for that as /drg. This is undoubtedly the content in 2025 where taking this into account matters the most. We can hit a whopping 25% intimidation procrate on Bumba, and get a 12.5% less damage taken bonus on chest vs it.

Omen: Unfortunately most of the bosses are Arcana, which is our weakest option to stack against. The food is bad for it, and we'd have to go /drk for the trait. It's pretty unlikely stacking Arcana killer helps us much here. Though it might be worth considering if you have an actual dark knight DD in the party, who can use Arcane Circle which will give another 15% Arcana Killer bonus for 3 minutes, which will probably make a big difference.

Sortie: A couple of these NMs are undead, which we are very well placed against due to malevolance, holy circle, and our extra +1% trait. Worth considering swapping these in specifically for the couple of undead bosses at minimum for when Holy Circle is up, you probably will hit the 50% killer proc rate cap and will pretty much just intimidate lock them the entire fight, lol

Limbus V3: As far as I know, most of these enemies we can use killer effects for, but tbh I assume you're just gonna use a more DPS savage blade spam oriented setup, cause the enemies seem to all just be exp trash fodder, so probably pointless to consider this.

I dunno if there's any other major content worth mentioning here. Ambuscade V2VD is always beastmen so killer effects mean nothing for them.

How high can we sanely go?

Right off the bat, we have all the following traits accessible, depending on content, assuming vs a boss (so the trait is halved, numbers below are post halved)

Natively Undead
/bst: Vermin, Bird, Amorph, Lizard, Aquan
/blu: Beast, Lizard, Plantoid,
/drk: Arcana (This one is bad enough we'll skip it though)
/drg: Dragon
/sam: Demon

Most of these also have a matching +12% food that lasts 5 minutes, which isnt amazingly long but probably long enough to count for many fights.

Killer Effect:	Amorph	Aquan	Beast	Bird	Demon	Dragon	Lizard	Plantoid	Undead	Vermin
Job Trait Bonus	/bst: +4%	/bst: +4%	/blu|/bst: +4%	/bst: +4%	/sam: +4%	/drg: +4%	/blu|/bst: +4%	/blu: +4%	Pld: +5%	/bst: +4%
Food Bonus:	+12%	+12%	+12%	+12%	+6%	+5%	+12%	+12%	+12%	+12%
Gear Bonus(including affinity earring):	+3%	+3%	+3%	+6%	+3%	+8%	+3%	+8%	+3%	+3%
Ranged Bonus	+2%	+5%	+2%	+2%	+2%	+2%	+2%	+2%	+2%	+2%
Weapon Bonus	---	---	---	---	---	+6%	+10%⚠	---	+10%	+10%⚠
Total Proc Rate: (Weapon)	21%(21%)	24%(24%)	21%(21%)	24%(24%)	15%(15%)	19%(25%)	24%(34%⚠)	29%(29%)	25%(35%)	24%(34%⚠)
LDT: (Weapon)	10.5%(10.5%)	12%(12%)	10.5%(10.5%)	12%(12%)	7.5%(7.5%)	9.5%(12.5%)	12%(17%⚠)	17.5%(17.5%)	12.5%(17.5%)	12%(17%⚠)
Effective Mitigation: (+Weapon)	29%(29%)	33%(33%	29%(29%)	33%(33%	21%(21%)	27%(34%)	33%(45%⚠)	39%(39%)	34%(46%)	33%(45%⚠)
Weapon ΔMitigation Relative Boost:	N/A	N/A	N/A	N/A	N/A	10%	18%⚠	N/A	18%	18%⚠

An important note:

1. The two MMM weapons (Ermine's Tail and Kogglemander) may or may not give +10% killer proc rate. They give you the monster trait of their type (vermin/lizard), so its possible this does not stack with the job trait 4% bonus. So it's possible the weapons only give closer to a +6% proc rate or so in practice.

Row Meanings:

Gear Bonus(including affinity earring)
Every affinity has a 3% earring associated with it, based on how strong the proc rates tend to be, and the fact that every 1% killer effect gives exponentially better returns than the prior, we will assume for a scenario where stacking killer effects matters and is worth it, you will always at least use the 3% earring.

Any additional "worth using without sacrificing much" gear is mentioned in this row. Usually an accessory that would just be competing with some meva/hp/acc stuff really.

Weapon Bonus
A couple traits have a mainhand weapon we can use that gives significant killer effect bonus. The purpose of separating this data out is so you can see numbers with vs without the weapon, in case you either care about dps, or you want to compare it to burtgang (tbh I think burtgang always wins if you have it)

For scenarios where you aren't doing any damage though, the enemy is spamming AoEs, and you care about magic damage more, these weapons might actually be worth considering though.

Total Proc Rate
How often the killer effect can be expected to proc, without vs (with weapon)

LDT
The "less damage taken" bonus from Founder's Breastplate (which is just your killer effect halved)

Effective Mitigation)
Proc Rate and Effective Mitigation compounded together, formula is as follows:
IE a Killer effect of 24% becomes:

Which means you effectively nullify about 33% of dmg, give or take (its a bit more complicated than that, but this number serves to give a good rough estimate)

Weapon ΔMitigation Relative Boost
This number compares the Effective Mitigation with vs without weapon, to show a rough delta of how much "less" damage you are going to be taking if you put the weapon on.

Note this is just damage, you'll also want to factor in the killer proc rate also protecting party members exponentially more.

For example, going from 30% mitigation to 40% mitigation, means going from taking 70% dmg to 60% dmg.

10/70 = another 14% less dmg taken

By comparison, Burtgang takes you from 50% PDT to 68% PDT, so you go from 50% dmg taken to 32%, which means you are actually taking 36% less physical damage net, relatively.

just a couple nitpicks

you can't sub drg in odyssey (as you don't get a sub at all)

killer effects are halved against anything that checks ITG, though i'm not sure if anyone has actually tested how that interacts with the breastplate

Interesting write up. Couple questions pop up in my mind.
How exactly are you using a subjob in odyssey?

Don't you need to be the target of the mob for killer effects to work? How are you planning on tanking in sortie past the first 2 seconds of a 30 second fight?

I was curious thanks. Since BST Empy body basically has founder's killer augment in it.

Sorry forgot the subjob part when doing the math, you are right, we will lose the 4% bonus we'd get from the appropriate subjob, that is correct.

I'd have to number crunch it all again without the bonus, but I think it's safe to say for several of the targets where you still can hit like 20% proc rate, it's probably worth it.

Is this a secondary halvening on top of the already mentioned halving on bgwiki?

Meanwhile this thread says its 2/3 instead of 1/2, which is pretty big if true

https://www.ffxiah.com/forum/topic/55720/killer-effects

And the bgwiki page cites no further sources beyond that

This bg thread draws the conclusion that food bonuses get halved, which could be troubling:

https://www.bluegartr.com/threads/131320-Killer-effect-testing

Messing with the ranged slot and food also changes how much magic evasion and SIRD you have on PLD. Losing burtgang is a significant enmity loss in a lot of fights too where you don't have a subjob.

Would be interested in seeing what functional sets you come up with not just what the theoretical max is

The NM reduction is separate per step. KI traits, KI from gear, circle effects etc. For gear it's 50%.

Food is separate and presumably halved, according to that thread.

The interesting question is this:

Does an intimidate proc also nullify enmity loss? I would assume so.

If you factor that in, at say a 25% proc rate, you are also nullifying 25% of the effects that would've caused enmity loss.

I tested all this stuff when Ferine Gausape was new.

Killer effects on NM's are reduced to 1/3 not by 1/3 so its a pretty wretched reduction. Cap for killer effects traits are 50, and you can cap it out with food and gear and atma etc.

I used to carry around stacks of killer effects cookies on bst. so I could cap it out. duration of that food was only like 5 min though.

so if I get Killer effect to 50, and I'm fighting an NM I can intimidate, the intimidation rate is around 16~17% whereas for non-Nm's its really 50%.

I guess SE long realized before players could even test how broken it is for a tank to intimidate 50% of a mobs actions. You can intimidate attacks, spells, and tp moves iirc.

I never did any testing about intimation and enmity loss though.

I think your chart is a bit off... tier 1 killer effect traits are 8% and tier 2 only takes it up to 10%

so in the chart at the top, not sure why you are listing 4% unless you are measure the damage difference and not the Killer effect difference.

I'm curious though.
The only way for bst to get dragon killer in Ody is with the demon earring and food right?
Cause i don't understand the Bumba part.
Even stacking all the enhances "xxx killer" effect, you can't transfer it because it doesn't come from a pet, so in order for it to proc you must be the target of the enemy aka have hate/tank it.
How does this help with Bumba?

this thread focuses on PLD not bst. i mentnioned bst because the mechanics for body piece and killer effects are the same and thats what I tested.

the OP forgot that there is no support job in Odyssey Gaol and assumed using different support jobs for various killer effects.

but yeah, you are right only a few pieces of equipment and food would give dragon killer to pld.

The idea being that if he can intimidate more, then its a huge tanking boon. especially when you intimidate AoE moves. However the killer effects are further nerfed on NM's so its not as effective as one would hope it to be.

Yes, it would be an awesome mechanic to exploit for tanking, but SE specifically nerfed it pre-emptively, so its practically useless.

To be specific how the killer effect nerf affects body piece augments its pretty simple.

it strait out nerfs the killer effect, which nerfs the damage mitigation and bonus from body piece as a secondary effect.

So I have 30 killer effect (15 of which mostly likely due to circle effect)to nm's ecosystem, the nm status reduces this to 10. so I get 5% damage mitigation and +5% damage dealt.

This is a separate step from the circle ability which is at 15% bonus.
So easy math example: 100 damage increases to 115, then 120. (that was multiplication, not addition: floor(100 * 1.15 * 1.05)
or reduce 100 damage taken to 81.

Wiki lists it as 1/2 instead of 1/3

And other people are saying 2/3

So it seems like we have a lot of conflicting info circling around.

My gut says that maybe part of why we have so many different conflicting results is maybe traits vs gear vs food arent all reduced the same amount, so thats why some people get different values?

Wiki says traits are reduced 50% and gear is not reduced.

Do you by chance have a link to your testing we can take a look at?

I personally did the testing with Falkirk and Byrth way before wiki put it up there.

I think it was largely confusion in communications as to why it wasn't recorded correctly on how badly nm's nerf killer effects.
For example if i say it reduces by 2/3 someone may misinterpret that as reduced to 2/3. so they think you do 66.7 damage instead of 100, while in reality you get 33 damage instead of 100.

as far as the reduced by 1/2, I don't know where that comes from. Laziness most likely. as a pure guess, they were always using body piece for augment and killer circle effect. so they didn't properly calculate 15% from circle effect separately from body augment portion. just a guess, cuz that was the most annoying part of the calculations. but easy enough to test when test circle effect separately, and body effect separately, then both together.

OR they are pulling the 1/2 from the fact that the body augment is 1/2 of the killer effect.

BUT Killer effects reduce TO 1/3 of the original potency VS Nm's. if you want to argue that, go retest it yourself.

our testing was in the Definitive Bst pet testing thread on Allakhazam forums which have long been defunct. YOu can sometimes find them in internet archives. I was surprised that one of the bgi-wiki refernce links went to an archive which actually had text from the thread. most of those reference links to allakhazam are just broken links now. I certainly don't know remember which link went to the archive.

its not hard to retest. go measure you killer effects. let something attack you for awhile. count the intimidations vs total actions. the numbers are pretty clear after 100, but get to 300~500 if you really want to be precise.

choose any lower level corresponding nm and do the same.

Furthermore, have a magic support job, cast a spell with and without the body piece and calculate the damage. use and nm target and non-nm target. compare the numbers. its pretty clear and easy. do the same with and without killer circle effect and body.

its fastest to see the number differences just casting elemental magic tests. you just miss the comparison of exact killer effect numbers that way.

Ok. I was so preoccupied with this that I had to go and retest it, and I see exactly where the confusion is.

the difference of whether you think its 1/3, 1/2 o 2/3 all depends on what it is in reference to. So everyone who noted these was correct, but not clear (including myself).

I'll throw some numbers here:

I redid the test as bst/blm. I went to Escha - Zitah (easy to get NM pops that won't die too quickly)

I wore Arktoi, Ankusa Helm +3, Totemic Jackcoat +3 and Totemic Trousers +3

The only piece I changed was The Totemic body for the Nukumi Gausape +3 for some tests. This made a change of int from 269 to 270 between samples where I used Gausape and not. I don't think the 1 int difference is significant.

I have 5/5 Killer effect merits. so 10 from the trait, 5 from merits, helm + Axe + Pants + Vorseals = 15 Killer Effects

I used Fire 2 for the spell.

NON-NM baseline was vs Eschan Tarichuk
In which I saw exactly what I expected from the formulas

baseline damage (No Gausape, No Killer Instinct): 799

Gausape with 30 in lizard killer effect: 918
(799 x 1.15 = 918.85; floored is 918)

Killer Instinct without Gausape = 918
both are exactly 15% damage bonus as expected

Killer Instinct + Gausap (with total of 45 Killer Effect: 1119
(Killer instinct bonus of 15% already shows 918 damage;
Gausape bonsus = floor(45/2) = 22; 918 * 1.22 = 1119.96; floored is 1119)

So we see exactly what the formulas predict.

I further tested fire 2 with exactly the same as above vs 2 zi'tah NMs: Ferrodon & Aglaophotis

Ferrodon:
baseline: 724
Gausape with 30 KE: 802
Killer Instinct: 796
Gausape + KI + 45 KE: 915

Aglaophotis:
baseline: 639
Gausape with 30 KE: 708
Killer Instinct: 702
Gausape + KI + 45 KE: 807

Yes Its interesting that the Gausape w/ 30KE is a little bigger than the Killer Instinct number, but both roughly the same percent increase in damage. Which indicates the calculation is generally right, but more complicated than this model. Killer Instinct is likely a direct percentage calculation, while the Killer Effect augment is likely more complicated.

On both NM's we see that the damage bonus from Killer Instinct is only 10% instead of 15%. This is 2/3 of the normal bonus from Killer Instinct, and only reduced by 1/3. This is NOT what I was referring to in my earlier post, but it is a correct description that the damage bonus was reduced TO 2/3.

The damage bonus from Gausape is roughly 10% also which is 1/3 of the initial Killer Effects value instead of 1/2. 10% bonus for 30 KE, and 15% bonus from 45 KE.

So the Job ability damage bonus is reduced by 1/3
The Equipment augment damage bonus is reduced by 1/3


I hope this is more clear than mud.

this test does not include intimidation rate. that might give insight into how gausape augment penalty is calculated in more detail.

> The damage bonus from Gausape is roughly 10% also which is 1/3 of the initial Killer Effects value instead of 1/2. 10% bonus for 30 KE, and 15% bonus from 45 KE.

Actually it's a bit lower than 11%

Now lets assume Vorseal also counts as a "trait" effect.

18% trait, 12% gear.

12% gear KE + (18% Trait / 2) = 12% + 9% = 21%

21% / 2 = 10.5%

Ferrodon: 724 * 1.105 = 800, vs your 802, probably rounding errors at that point because SE likes to store stuff in 1/256 increments.

Aglaophotis: 639 * 1.105 = 706, vs your 708, once again off by 2 so I can assume its the same thing, 1/256 rounding errors or something.

You can see how this happens here:

60% of your KE is from traits

If you halve only that, you go from 60% + 40%, to 30% + 40%

So you go from 100% of your KE to 70% of your KE

So you lose about 30% of your KE vs an NM in this scenario.

Easy way to check will be to repeat the test but with a much larger amount of KE from gear, and less from traits.

And that means you go from 50% of your "normal" KE effect as dmg bonus, to only 35% (50% * 70% = 35%)

Which is very very close to 33%, but not quite.

Also, important to avoid testing with food to hit that higher number, because food might not work the same way gear KE does

Im fishing for a bunch of KE gear right now to see if I can assemble enough to get good numbers.

Its magic damage. Its not a rounding error. There would not be rounding, there would be flooring, which means it would not round UP higher than your calculation.

if it were an issue of fractions with a base of 256:

26/256 = 10.15%
27/256 = 10.54%
28/256 = 10.93%

The actual number: 708 - 639 = 69; 69/639 = 10.79%
This is not a fraction of 256

The Ferrodon number comes to 10.77%

That could be a flooring issue in a calculation between the different samples. I think its pretty consistent in how close it is to 10.8%

The amount it increases compared to the 10% from killer instinct vs nm's is consistently higher. which means 10.8% is probably a reliable estimate, and figuring out the exact formula might be satisfying but no practical benefit.

The difference in the testing thread on ffxiah referred to by the bg-wiki page on Killer Effects only indicates the difference between traits and gear bonuses, is that trait bonuses only apply to the killer effects that job has, while gear bonuses usually add all killer effects traits. That's the only difference there. Its not a difference in values between the 2. The only gear difference in value, is what I showed with my numbers.. the mysterious .8%

ie: Beastmaster has no undead killer. so putting merits into killer effects + does not add undead killer. However, equipping arktoi DOES give undead killer up to 5%.

there is no basis for separating NM penalty by what source the Killer effect bonus comes from. And if you DO want to test that, then assuming vorseals 3% is one group or another is a faulty method. go get your own data to investigate that.

I'm just saying your numbers align with what bgwiki says: only trait based KE gets halved, gear KE doesn't, thus you only lost 1/4 of your total KE

However, like many other stats, it seems there's just a KE I vs KE II perhaps, that is to say 2 pools (much like how many other stats work)

Pool 2 is gear KE

Pool 1 is everything else. Buffs, traits, food, vorseals, etc

I'd propose Pool 1 gets halved, so it's not just traits.

Which is why ppl found food also has halved effect vs NMs, and why your vorseal effect was halved.

The math lines up with your numbers there. That's why you got 10.8% and not 10%.

Considering the fact so many other stats differentiate gear stat from other sources (IE Haste), this wouldn't be a huge surprise either.

I don't have the gear to test with bst, or I'd test myself.

I can test intimidation rates though.

Please show me where you see this on BG wiki. I don't see it on the Killer Effects page, any of the Empy armor pages, the founder's breastplate page or the pages for the circle abilities.

I already tested intimidation rate just now on ferredon w/ 30KE same gear as before, did not use killer instinct at all.
Intimidation rate is 20% instead of 30% as expected. so if you just nerf the killer effect, the secondary effect nerfs the damage bonus.

This does not comply with your strange theory about different Killer effects categories between gear and job trait.

I just showed in my previous post why your calculations don't match.

https://www.bg-wiki.com/ffxi/Category:Killer_Effects

"The potency of Killer Effects gained by Job Traits is halved against Notorious Monsters, but Killer Effects gained from gear is unaffected."


18/2 + 12 = 21%

1% off from 20%

What's your sample size? We can run a p test to see if 21% is outside or inside .5% threshold of confidence on the sample.


The test is easy btw, just take off your KE gear and don't have vorseal, so you only have 15% KE trait.

Basically we just need two different data points vs an NM to draw a line between.

If you get a ~7.5% proc rate and ~3.75% dmg boost, then bg wiki is right.

If you get a ~10% proc rate and ~5% dmg boost, your theory is right.

Ideally though we'd wanna gun for a way higher KE though, like 40%+ , that way the gap between the two possibilities becomes waaay bigger and which one it is will be way more statistically evident.

But theoretically just slapping Ferrodon with a Fire2 and 0 KE gear amd only 18% KE from trait+vorseal will be a decent enough data point to show the trend line.

I appreciate your contributions! I'm testing it out on pld tonight, what tool do you use to track intimidation rates, is there a parser that can pick it up?

Aight, did a parse of 1000 vs bubbly bernie to start:

https://gist.github.com/SteffenBlake/fc1f14cfffc8bd49510429640201948c

tl;dr of the math: Looks like its about 3x more likely gear killer effects are halved, than 2/3rd'd

Getting a multiplier of 0.56 on my killer proc rate at 1000 sample size, which is a fair bit closer to 0.5 than 0.66

I posted all my math/gear at the bottom as well with 2 tailed p value z tests