^ Title.
Since we don’t see flat resist values anywhere, are they the same?
For example, does acid spray reduce resists by 28% across the board or is it just 28 more dmg?
28 reduced resists is functionally the same as -28% resistance, with it working like the first case you mentioned. The difference is that multiple instances of flat resist reduction won’t stack with each other, with only the highest values being counted.
% rr or -% RR or flat RR? Cause they are different.
-% rr stacks with itself indefinitely. Flat RR only highest value applies (global flat-manticore, elemental flat - elemental storm and physical flat- Break morale). There are also some items that have various flat RR
And finally % RR applies last after the above two. %RR works best if you have so much RR that you’ve brought it below 0%. So if an anemy has -50% fire resistance, Viper constellation 20% rr will bring it down further to -60% resistance or so.
Also keep in ming that %rr needs a %weapon damage value to apply. It applies at full strength with 100% weapon damage.
Exception is Hand of Ultos devotion that is a spell debuff itself and doesn’t need %weapon dmg. So it’s great for caster too.
Here is an old sheet that explains RR more visually and organized
Yes, that clears it up. Than you 
Oh, thought %rr & -%RR were the same thing. And thank you for the pic link. Just learning GD mechanics, so this was incredibly helpful 
Really? That’s a new one… so viper activated by fiend is not 20%reduced but 5.2%reduced?
Not sure if everyone read this so I’ll just link it here in case. Basically order doesn’t work the way we originally though.
Viper activated by fiend will have 26% of it’s power so 5.2 indeed. Unless you have other %weapon dmg sources or ultos devotion
I don’t understand this. How does viper even need to be activated? In viper devotion, there is no explanation about anything like that, viper doesn’t have a proc, so it doesn’t have to be bound to anything. Well not just doesn’t have to be but cannot be, to put it better.
However yes I always found stuff like viper strange because I never understood how and when does it even activate, what triggers it? Because it doesn’t say anywhere, it’s easy with most other rr devotions and skills, you clearly understand that manticore activates on proc, break morale activates when you use the skill etc.
But what is the “activator” for that last viper node? Could someone clarify that a bit because I get really confused when it comes to those “passive activations”, or should I just say misterious activations because nowhere is it clearly written how and when do they happen? There is a lot of stuff like this in the game, I am not just talking about viper.
And one thing that I never liked about gd is that there is a ton of stuff that you need to do your own research on if you want to get a really top tier build in the end. For all the stuff that devs didn’t bother to put descriptions in the game or at least in some kind of an official guide, I think it’s just not fair to have them in the game at all.
Just a quick comparison, even the hardest fighters usually have something called frame data for serious players to study and learn when needed. It seems that in Grim Dawn getting to advanced mechanics is just a matter of dedicated members of community, it’s almost like the devs have hidden those things away from players intentionally.
As much as I like this game in general, that problem bothers me just as much. Whether the devs are aware of that fact or not, but stuff like that can be one of the main triggers that produce what we sometimes call an “elitist” or even toxic community. Don’t get me wrong, I’m not saying most members on the forum are acting in such a manner. On the contrary, most members here are still quite helpful and pleasant (luckily). But I know from my personal experience in some other communities, as soon as you have an overly complicated mechanic (or a mechanic that is not properly described for players to gradually learn about it on their own), you usually (9/10) times get a toxic community in a given ammount of time.
Not before long you will get a group of people who grinded their way to certain knowledge about the game who then almost hold it sacred to their small circle. Those people then brush newer players off with comment if the range of “git gud” and similar that are of course not helpful at all, new players don’t feel welcomed and everyone who is not really “hardcore” will probably soon quit the game and move to something else. And again, I am not saying that is happening on our forum and I have a lot of respect for this forum just because of the fact.
And another thing, I’m also not saying that games shouldn’t be complex and have a lot of depth to it. But if you make a game that is complex and has depth to it, you should at least really clarify things that needs to be clarified. Yes I know Crate is a small team and I have always applauded them for their amazing work, however that doesn’t mean the game is perfect.
So I am just giving my personal feedback and opinions if they would want to make their next arpg even better. Or at least include more complicated stuff like that in the official game guide or something, so you won’t be bothering casuals, and serious players would still have a reasonably easy to access material to learn from. Even though one could argue what is complex, and one of the numerous devotion choices shouldn’t really be that complex in it’s function (imo). I think in Grim Dawn you would be sursprised to see how many longtime players are probably still using certain things wrong after countless hours, or should I rather say not to it’s full potential. And they cannot be blamed for that one single bit, everybody will be using stuff in the game with supposedly clear descriptions in a good faith that those descriptions do indeed cover everything there is to know. Sadly there are usually 2 to 3 or 4 layers under those easy to understand descriptions. If I didn’t regularily read the forums I still wouldn’t know shit about RR stacking. And you must understand that we are not talking about some obscure thing that probably adds a few percents of dmg or something. On the contrary, this is one of the main factors that differentiate between a bad/mediocre to a good/toptier build. This game just doesn’t explain important stuff to players, it never did, game guide is not helpful at all. Of course the importance of RR and their respective stacking mechanics are far from the only thing I wouldn’t know shit about. And I must say that after more than 1k hours in the game I am still constantly in a slight fear that I might be missing something and my build is still really lacking because of that. You can call this a slight paranoia, but one that is definitely grounded in some real objective issues that this game has.
Just my 2 cents, I initiallly didn’t intend to go into all that, but I always get a little bit triggered with this topic, and like I said in Grim Dawn there is really a lot of stuff that you have to figure out by doing a lot of research or with help of other community members who have done incredible ammount of research.
For the last time, information like this should really definitely be accesible way easier. Or make a warning that goes something like this at least: “Don’t waste putting points into that constellation if you don’t know exactly what you are doing, because even the devs didn’t have a slightest idea how this will work out when they designed it”.
LOL
Viper is activated by weapon damage. Skills that deal %weapon damage and default attacks will apply the RR from the last star, modified by the % of weapon damage (up to 100% power). As stated earlier, fiend would trigger it, but at a much lower power level because it is less than 100% of weapon damage, but cadence would only trigger it at listed value, not 400% of listed value or whatever.
I understand your frustration with the sometimes sparse descriptions of tricky inner workings of the system, but I find that there is some fun to be had in hunting down the truth about this mechanic or that mechanic. Plus, if you have questions about specific mechanics, the forum can help you out 
Yes that’s why I am praising the forum in my earlier post. Like I said given the fact of the game’s complexity in certain aspects and lack of “official information”, I would definitely expect the forum to be a much more unfriendly and “elitist” place, which is thankfully not the case at all.
Ok back to the original topic. So I still don’t understand where the decision on what triggers viper is made? Let’s say you are using cadence plus fiend? Which one of those “activates” viper? Does it get activated by both, how does that get distributed?
Think of it like a “psuedo” weapon DoT.
Highest value overrides until the duration [of the highest] is finished.
(max. 100% of the effect and scales with %wpn dmg)
After analyzing the results of the experiment, one can come to the conclusion, that correct RR order are next:
First “-Y% Resistance” additive debuff,
then “Z% Reduced” multiplicatively,
and last “X Reduced” Additive.
What about stacking same type of RR, all rules are save:
Works only strongest of Reduction of each type; (Strongest of X and Strongest of Z)
All other different source debuffs stacks. (All Y-s are summed over)
Wow… I have just been picking up resist debuffs everywhere… should have known was some intricate formular behind that stuff 
Let me see. My lightning warder:
raging tempest: - 35%
viper: 20% reduced
hand of ultos: 25% reduced
Elemental storm: 32 reduced
That would mean viper is “pointless” (for the debuff atleast) when ultos is active.
Resist=(R0+Y)*(1-sgn(R0+Y)*Z/100)-X
Where: Resist – Final enemy Resistance
R0 – Initial enemy resistance
X – “X Reduced target’s Resistance” (For current example X=43)
Y – “-Y% Resistance” (For current example Y=-30. Be noticed: not 30, -30% or 30%)
Z – “Z% Reduced target’s Resistance” (For current example Z=51. Be noticed: not 51%)
For a target with 50% lightning resist:
(50-35) =15
15 *.25 = 3.75
3.75 - 32 = -28.25
is that right? (not sure about the sgn part. If I read the wiki right that makes 1-1 = 0 basicly making the whole equation 0 - 32 = -32 ??)
15 *.25 = 3.75
For the %RR portion.
This should be 15* (1-.25) or 15*0.75
For a target with 50% lightning resist:
15 *.25 = 3.75
For step 2:
%RR would be apply to monster resist as resist * (1-%RR)/100 or 0.75 of current.
Viper may not be useless, depending on the situation. For a full caster, then yes. If you are weapon-proccing HofU, then viper might be useful when HofU fails to proc, as Viper is guaranteed on hit.
Question; Does the RR from Acid Spray stack with something like Elemental Storm?
No. Debuffs with “X reduced” do not stack with each other.
Partially yes, Elemental Storm will only override the elemental resistances, all other resistances will still get reduced by Acid Spray.
Just read the thread. Thanks…
This will change the direction on some character building for sure…
Sent from my Redmi Note 3 using Tapatalk
Exactly what I was wondering about. Thanks
Truly that is the reason I am lauding the discussion in my prior post. Like I said given the reality of the amusement’s unpredictability in specific viewpoints and absence of “official data”, I would anticipate that the gathering will be a significantly more threatening and “elitist” put, which is fortunately not the situation by any means.