Poison Damage Explained
or, "Why'd my damage go down when I added another poison item?"
Poison is a bit of a mystifying topic and I've seen plenty of questions that aren't quite cleared up by the game guide's explanation, so I figured I should write my own.
One of the more important things to know is that while tooltips will tell you that a poison does X total damage over Y length, the game actually cares about a poison's damage per second (DPS) and total length*. So when you see a Curare tooltip for 10,000-12,000 damage over 2 seconds, you should instead think of it as a 5,000-6,000 DPS poison that lasts 2 seconds.
* Strictly speaking, the game internally represents poison as a bit rate (measured in 1/256s of damage per frame) and duration (in frames), but because game logic is locked at 25 frames per second I can keep it simple and talk about the equivalent DPS and seconds instead. Median's damage numbers are large enough that any inaccuracy will be small. If you insist on knowing the internal numbers, multiply DPS by 256/25 to get the bit rate and multiply seconds by 25 to get frames.
The two poison resistances
You may have heard that poison pierce ("-% enemy poison resistance") double dips. The reason for that is that there are two poison resistances, and pierce works on both of them.
The first is just called "poison resistance" and works like any other resistance by reducing the amount of damage taken. In Hell, most enemies have 35% poison resistance and most bosses have 70% poison resistance. If you don't have pierce, this will directly reduce the DPS of your poison by 35% or 70%. If you do have pierce, you can reduce enemy poison resistance down to -100, which doubles your poison DPS.
The second is "poison length reduced" (PLR) and reduces the duration of poison. The highest PLR enemies have is 75%, which is reduced to minimum (-100) with 175 pierce. Most bosses have 50% PLR. As a player, your PLR is subject to the difficulty penalty (-100 in Hell) and the usual resistance cap of 75%, so to be at maximum you need to stack to 175%.
Some enemies will also absorb up to 60% of your poison damage and all bosses will cut your poison length in half. There's nothing you can do about these, but it's still good to know.
Poison stacks... sort of
Two other things you've probably heard about poison is "poison can't kill you" and "poison doesn't stack". I'm here to tell you that both of those are wrong. It's true that poison damage over time can't kill a player and doesn't stack, but whenever a poison is applied, for the first frame it works just like any other elemental damage:
- First frame deals full damage (4% of DPS) instead of any existing poison damage over time (against monsters) or in addition to it (against players, mercenaries, and minions)
- First frame can kill a player or a monster
- First frame does not trigger "chance to cast on kill" if it's a spell
After that first frame's damage is applied, the poison with the highest DPS is picked as the damage over time to stick on the enemy. It doesn't matter if it has 1 frame left, if it has more DPS than the other one it'll get picked. A 10,000 DPS poison with 1 frame remaining will be picked to stay over a 9,999 DPS roll with 12 second duration. Once a poison is picked to stay, it has the effects people think of:
Damage over Time
- Only one poison sticks around and deals its damage over time
- Poison DoT can kill monsters and hirelings, but will only reduce players to 1 life
- Poison DoT can trigger "chance to cast on kill"
The most important consequence of this is that continuing to hit enemies with multihitting poison skills can increase your poison DPS. For example, at point blank range, Lorenado tornadoes can all hit the same target for 3-4 frames each, which can result in almost a full second's worth of DPS per cast!
Unconfirmed, needs testing: CLoD's Whirlwind, while dual wielding, makes an attack with both weapons every 4 frames. If Median's Whirlwind works the same way, you will get two poison hits every 4 frames, and your poison DoT for the other 3 frames, so continuing to spin on your target results in 25% more damage than just the poison DoT. If Gale Force also hits the primary target, it's closer to 50%.
Scaling poison spells
Poison spells are pretty simple to scale. All of these work:
- -% enemy poison resistance (increases both DPS and poison length)
- + skills (typically increases DPS)
- +% spell damage and +% poison spell damage (increases DPS)
- energy and spell focus (increases DPS)
- +% to poison skill duration (increases poison length)
Poison duration is not affected by the Continuity mastery, which only affects the duration of buffs and debuffs.
Scaling poison weapons
Poison weapon attacks are significantly more complicated. Right off the bat, I want to make note of the following stats:
- weapon damage multiplier (e.g. Whirlwind's 150% Weapon Damage) will multiply your poison DPS
- -% enemy poison resistance works
- + skills will increase poison damage you have from skills like Curare, Way of the Spider, Snake Stance, and Amatoxin
- +% spell damage does not work (even though page 1 of your character sheet will lie to you and say it does), but there is an exception I want to talk about.
- +% to poison skill duration does not work (except for Gladiator's Dominance + Snake Stance)
Now, the spell damage exception: % spell damage applies to direct melee hits and only to direct melee hits. This is why Zeal sorceresses are a thing in classic LoD; the elemental damage of Holy Shock and Enchant is multipled by the spell damage bonus of Lightning Mastery and Fire Mastery. This still happens in Median, but 99% of the useful melee skills use some kind of projectile so it doesn't come up much. The most important exception is Whirlwind, which does benefit from % spell damage. The Gale Force passive and any other procs you might be using will not, but a Whirlwind user can get a fairly significant single-target boost from % poison spell damage.
With that out of the way, on to poison sources.
Every skill and item that you have adding +X poison damage over Y seconds counts as a poison source. More sources will always add their DPS to your total poison DPS, but duration is more complicated. The total duration of all sources adds up, and then is divided by the number of item sources you have - skill sources are free duration! Let's go through some examples.
Example: adding item sources
► Show Spoiler
Example: adding skill sources
► Show Spoiler
Example: pierce and duration
► Show Spoiler
- Don't trust page 1 of the character sheet to tell you your weapon damage correctly unless it's 100% physical or magic damage.
- -% enemy poison resistance is an extremely good stat and you should try and cap it as soon as possible.
- Continually casting Lorenado or Scorpion Blade does increase your damage whenever you can hit an enemy with 2 or more projectiles.
- To get maximum damage and duration out of a weapon poison, you want to have one item providing poison damage, your class skill, and Amatoxin from Astrogha's Moon,Astrogha's Moon
Angel of Death
Set Bonus with 2 or more set items:
Maximum Poison Resist +2%
Poison Resist +75%
Set Bonus with complete set:
Wyrd: Stuns Target for 0.2 seconds
Wyrd Cooldown Increased by 0.3 seconds
-25% to Enemy Poison Resistance
+23 to Amatoxin
Slow Target 5%
Runeword Level: 100
3% Chance to cast level 1 Time Wave on Melee Attack
+(200 to 300) to Attack Rating
-(21 to 25)% to Enemy Poison Resistance
+(2 to 5) to Amatoxin
(3 to 5)% Chance of Crushing Blow
Attacker Flees after Striking 20%
+(115 to 143)% Enhanced Defense
+(30 to 50) to Vitality
Poison Resist +25%Blacktongue. But if you only care about DPS, stack away.Blacktongue
One-Hand Damage: (101 - 119) to (110 - 130)
Two-Hand Damage: (165 - 195) to (169 - 200)
Required Level: 100
Required Strength: 300
Item Level: 105
Strength Damage Bonus: (0.16 per Strength)%
15% Chance to cast level 44 Rotting Flesh on Melee Attack
+25% Bonus to Poison Skill Duration
+(120 to 160)% Enhanced Damage
+(40 to 60)% to Poison Spell Damage
-(20 to 35)% to Enemy Poison Resistance
+(14 to 20) to Amatoxin
Slow Target 15%
Maximum Poison Resist +(1 to 2)%
- Miasma (without the Sorceress passive for it) constantly applies a low-damage first frame poison to enemies, so it prevents a monster from taking any damage from your other poison damage over time until they move off of it.
Credits & References
Thanks to Ben- for answering questions about specific poison sources and enemy poison length reduction in Median.
The Tao of Poison v1.09 by Bkelly
Calculating Poison Damage v1.10 by onderduiker
Basin Wiki on Poison Damage, also by onderduiker