Dota Allstars Library Guide: Guide to Damage Block (Vanguard, PMS, Stout Shield, etc.) by Phoenix.dss Download Dota Allstars 6.79b
arrowLibrary Guide > Guide to Damage Block (Vanguard, PMS, Stout Shield, etc.) by Phoenix.dss

Guide to Damage Block (Vanguard, PMS, Stout Shield, etc.) by Phoenix.dss

Created by Greater Bash on 2009-12-07
Compatible with version 6.64

Viewed 21048 times
Commented 24 times

Rating: 99999
Guide to Damage Block This guide was originally made for the PlayDota forums which you can find here in the original format. I'm not very accustomed to BBCode of so if any mod can improve this guide's look please feel free to do so. This is a Mechanics Guide. I'll hate to see long strategy discussions in this thread. Also, I expect this guide to move into the Library Section.
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 Table of Contents 

  1. What is Damage Block?
  2. Ways of Damage Block
    • Stout Shield
    • Poor Man's Shield
    • Vanguard
    • Kraken Shell (Tidehunter)
  3. Mechanics of Damage Block
    • What type of damage is reduced?
    • Interaction of Damage block with Armor
    • Stacking Damage Block
    • Actual chance of Damage Block
  4. FAQs
    • Krobelus' spirits vs Damage Block
    • Illusion damage vs Damage Block
    • Mana Shield with Damage Block
  5. Credits 


I. What is Damage Block? 

The reduction of the damage you receive when you get hit by anything with damage typephysical. This means it will reduce damage from normal attacks and from spells with damage type 'physical' or 'mixed'. All Damage Blocks are based on Hardened Skin Skill. 


II. Ways of Damage Block 

Currently, physical damage can be blocked by 4 ways in DotA:- 

1. Stout Shield 
Gives a 60% chance to block 20 damage if the wielder is melee, or a 60% chance to block 10 damage if the wielder is ranged. 

2. Poor Man's Shield 
Gives a 100% chance to block 20 hero damage and a 60% chance to block 20 non-hero damage if wielder is melee. 
Gives a 100% chance to block 10 hero damage and a 60% chance to block 10 non-hero damage if wielder is ranged. 

3. Vanguard 
Gives a 70% chance to block 40 attack damage. 

4. Tidehunter's Kraken Shell 
Gives 100% chance to reduce 7/14/21/28 damage. 

Only the details of damage block are written above. Other effects of the items/skill will not be discussed here. 


III. Damage Block Mechanics 

1. Damage Block reduces physical damage type. This may be due to normal attack or by spells with physical damage (like Slardar's Slithereen Crush) or by spells with mixed damage type (like Beastmaster's Wild Axes). 
Refer to this for more information on spell damage type. 

2. Damage Block occurs before any armor reductions. 

Example: Let us suppose your hero has 5 net armor (23% damage reduction approx). You've made a Vanguard and you get hit by 100 damage, then your hero will have: 

1. a 70% chance to take 46 final damage. [Damage Block from Vanguard triggers. Damage Received = (100 - 40) x 0.77] 
2. a 30% chance to take 77 final damage. [Vanguard did not proc. Damage Received = 100 x 0.77] 

Refer to this for more information on Order of Damage Calculations. 

3. Stacking Damage Block - When our hero has more than one damage block source... 

Only one Damage Block can proc/trigger at a time. The last acquired damage block is checked first of all, if it doesn't proc only then the next one is checked. 

Items counts as acquired when they are picked up and abilities counts as acquired when you learn the first level of the ability (any subsequent leveling will not make the ability count as re-acquired). 
The chance that any of the sources you have which provides damage block will trigger follows a diminishing stacking pattern as can be seen by the generic damage block formula. 
The following formula is used to calculate the chance that any source you have will trigger: 

Chance to block = 1 - [(1-X)*(1-Y) ...] 

{X, Y, ... } are replaced with the percentual chance that the source will trigger described as a decimal value. 
A. If you buy a Vanguard first and then level Kraken Shell , the damage block fromVanguard will never trigger coz Kraken Shell (with 100% chance to proc) was the last acquired Hardened Skin Skill. But you can drop and repick the Vanguard so it becomes the last acquired damage block item and would be checked first for damage block. 

B. Let us suppose you complete a Vanguard and then buy (an additional) stout shield.The last acquired Hardened Skin here is Stout Shield so it will be checked first for damage block. Your hero will have: 
-> a 60% chance to block 20/10 damage if the wielder is melee/ranged. 
-> a 28% (70% of remaining 40%) chance to block 40 attack damage. 
[So, basically you're at a loss here. Drop the Vanguard and pick it up again to make it the last acquired item.] 

C. How will 2 Vanguards stack with each other? 

If your hero has 2 vanguards, your chance to block 40 damage is 91% = 70% (last acquiredVanguard procs) + 21% (70% of remaining 30% if the last acquired Vanguard does not proc but the other one does) 

Note that in NO case 80 damage will be blocked (a common misconception). 

4. Actual chance of Damage Block 

The chance to trigger Hardened Skin is based on Pseudo Random Distribution. This makes the actual chance to block a bit lower than the stated value. 

Skill/Item Stated Chance Actual Chance 
Stout Shield | 60%| 53% 
Poor Man's Shield | 100%(hero damage) | 100%(on/off not based on PRD) 
Poor Man's Shield | 60%(non-hero damage) | 53% 
Vanguard | 70% | 60% 
Kraken Shell | 100% | 100% 

For more information on Pseudo Random Distribution read this . 



1. Krobelus' spirits/ghosts vs damage block. 

Q. Will a Vanguard help me reduce damage from Krob's ulti? 


Krobelus' spirits have the ability [Locust] and damage block does not reduce damage from units having Locust ability. 
Besides Krobelus spirits, dummy unit summoned by Corrosive Skin (Viper) has the locust ability that always deals 1 damage. 

2. Images vs Damage block 

Q. Assuming a PL has 100 base damage then his images would do 25 damage when they hit a target. But if it gets blocked by a vanguard would the damage be (100-40) * .25 = 15 damage or (100 * .25) -40 =0 damage? 

0 damage 

The illusion damage reduction is applied before damage block. 

3. Mana Shield with Damage Block 

Q. Will the damage reduction happen before mana shield absorbs the damage ? or will manashield absorb the damage and then damage reduction works? 

This has two possibilities: 

A. If you acquire damage block first and then activate mana shield - In this case both work together with the mana shield reducing the incoming damage first of all. 

B. If you acquire damage block after activating mana shield -In this case mana shieldactivates only if damage block does not trigger. 

Here are the results by a test done by Cáno 

Damage dealt by Centaur when: 
Mana Shield off, no Stout Shield - 30-31 damage, 
Mana Shield on, no Stout Shield - 15-16 damage, 
Mana Shield off, with Stout Shield - 30-31 or 26 damage, 
Mana Shield (turned on first), with Stout Shield - 15-16 or 26 damage. 
Mana Shield on, Stout Shield (acquired before turning Mana Shield on) - 15-16 or 9 damage 
Pro-tip: Always deactivate and then reactivate mana shield after making a damage block item. 

V. Credits 

- e00E 
- Antiweltteilchen 
- All mech fags of forum.


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This guide is checked and updated based on Icefrog's DotA 6.64 map.


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24 By hassan590 2011-08-24

wat if we use tallisman of evasion??

23 By Masked_Lord 2010-11-27

Dispersion is the most stackable dmg block ......

22 By tasik 2010-08-02

dispersion doesnt work like "last acquired thing triggers first".

-i got dispersion after a PMS and i saw dispersion activating
-i got PMS after dispersion and i saw dispersion activating

21 By Vodec 2010-06-27

I would also like to know about spec dispersion.

20 By [D][Morning]Star 2010-06-18

I hate MATH!!!!!!!!!!!!!!!!

19 By shocker500 2010-06-14

Does VG reduce healing from abbaddon's borrowed time?

18 By harrisp97 2010-06-01

How about spectre's dipersion? Please help me

17 By nigielee 2010-05-25

Does the PMS block stack?

16 By Ephemeral96 2010-05-20

NIce Stuff......And Guide.......

15 By Kytera 2010-05-09

good stuff. but i have couple of qu--s
-If stout shield blocks 20 damage, will vanguard try to block 40 dmg after it?
- and is the chance of nonblocking dmg can effect the chance of second item to trigger? (2 vangs - 70% of 30%) why not of 100%

14 By aaronli163 2010-04-09

great, nice info! 8/10

13 By zalalo92 2010-04-04

luv this stuff.
thats all

12 By twohotsamurai1 2010-04-04

11 By Fhau_emo 2010-03-15

Very go0d guide. Nice

10 By invinsib1e 2010-02-02

that is good neva knew that!

9 By Vesperia 2010-01-20

Never knew about the mana shield thing.. Good guide..

8 By mhkk001 2010-01-07

goooood guideeeeeeeeeeeeeeee

7 By akhilesh 2010-01-07

good guide

6 By frano3 2009-12-13

Complicated.But still an important guide,and also an link-answer for "medusa with vanguard" trolls.

5 By Greater Bash 2009-12-13

But at least we are able to warn/ban them then.