Density Scaling of Devouring Arrow

Hi there! It’s time for another informative math post explaining why increasing monster density greatly increases the damage dealt by Devouring Arrow.

With the new release of the Gears of Dreadlands set alongside a major buff to the Ninth Cirri Satchel, many players are now using a Devouring Arrow Strafe build. Specifically, the important aspect to focus on is the guaranteed pierce chance of Hungering Arrow.

To start, let us assume the Hungering Arrow is fired from a distance where it hits a single target exactly 5 times and there are no walls or other obstructions that prevent the arrow from doing so. With a missile dampening elite, many more pierces are possible, but for this analysis we will assume such an enemy is not present.

Next, assume there are n targets stacked up on top of each other, this is somewhat possible with a “pixel-pull” like Barbarian’s Ground Stomp - Wrenching Smash.

So now the question is:

How does the total damage of a single Devouring Arrow scale with the number of targets n with some fixed amount of area damage a%?

To answer this question, we need a couple facts:

  1. Devouring Arrow’s damage is multiplied by (1 + 0.7*pierce_count). So that the first hit does normal damage, the second does 1.7 times, third 2.4 times, etc.
  2. Area damage is applied to all other targets per hit. We will assume a fixed amount of a% area damage at a 20% proc chance, we can simplify this to 0.2*a area damage at a 100% proc chance for the expected value over a large number of trials.

So now let’s simulate the entire process where the base damage of the Devouring Arrow is 1. On the first hit on the first target, the damage dealt is 1 and all other n-1 targets take 0.2*a damage.

Now the arrow hits the second target for 1.7 times the damage and 0.2*a of that amount to the other n-1 targets:

Following this pattern to the kth target, we obtain:

Now, how many hits do we get? Well since we assumed the arrow would hit an isolated target exactly 5 times, the arrow would hit n times (piercing the stack of targets), turn around and hit n more times, etc. for a total of 5n hits. Now we can sum the formula above for k = 1 to 5n:

Note that this reveals that Devouring Arrow scales cubically with the number of targets since the highest order term of n in the equation is n^3. The coefficient of that term involves the area damage total “a” which means area damage is extremely important for this build!

To summarize, Devouring Arrow’s potential depends heavily on the number of targets present in a close proximity. While area damage scales very strongly with density, so do the number of pierces. This interaction leads Devouring Arrow to have cubic order scaling with the number of stacked targets in very high density.

TL;DR: Get as much area damage as you can for Devouring Arrow and try to stack things at tight as possible with Ess of Johan, Leonine-enhanced Bolas, or a supporting player (e.g. Barbarian). Also, Missile Dampening allows for many more pierces to occur!

Thanks for reading another of my math posts!

15 Likes

Very nice indeed, another sticky worthy thread.

Very relevant to the current patch too.

1 Like

What about 4p ? Won’t it lag in higher GRs with so much AD ?

1 Like

This explains why I’ve found vile swarms and their stackability feel like a bad mob type as they melt and die before I can get any damage on elites. Progression is OK but unable to get those elite globes even on a reasonably dense Festering.

What’s the explenation for missiler dampening giving so many pierces?

Great post btw <3

We can get AD by Paragon (50), on Sholders (20), Arms (20) and Weapens (2 x24) or a Quiwer (20) with is round about 134-138.
Another slot for AD are the two rings (2x20). Do you think it is worth to change AD for the +dmg rolls?

Btw, thanks for posting :+1:

HA lasts until it travels a certain distance or hits a wall.

The turn around aspect is based on time traveled.

Missile dampening slows the distance traveled, but the turn around time remains the same. HA basically ends up never leaving the elites hit box, and wastes very little travel distance not doing damage.

2 Likes

Nice explanation/derivation, though this seems hardly surprising, as normally when both area of effect (i.e. the ability of a skill to hit multiple targets) and area damage are factored in, we already get quadratic scaling. The additional cubic term then shows up because Devouring Arrow’s single target dmg scales off of density.

1 Like

Thanks Iria, that was a nice explanation and +props for the extra maths :slight_smile: I’m currently trying a build which seems to be working quite well and is based on max AD, no CD on any items, with Zodiac in the cube to give the CD for permavengeance.

I’m using FB and Dawn, 172% AD, using FoK/BA, Wolf, RocketStorm, Veng/DH and Zodiac in the cube with Cirris. With my meagre 1700 paragons I’m happily doing GR120-ish and could probably push a few higher with fishing.

I decided to try the AD option instead of CoE, thinking I could get the 1.5x extra from AD instead of the ring and it might be a bit easier to play as there’s no special timing involved. Well it’s certainly a lot easier and I’m having fun with it :slight_smile:

There are some nice extras with this build - ie Amethyst in helm for +23% life, and Zod causes more wolf and FoK activations than I’d normally get.