Added 11/8/2020 Source: https://bbs.mihoyo.com/ys/article/2204156 (Dated Oct 14, 2020) Translated by: @KluEvo, @sacstanxiang & @Azri K.
By: Bobrokrot#0111 Added on 2/12/2021
By: Bobrokrot#0111 Added 12/6/2020
Theory Fatui armor breaks mostly off elemental reactions and armor breaking effectiveness depends on strength of aura application.
Fischl E vs hydro armor: We can see fatui armor breaking from electro-charged procs, not Oz attacks.
Lisa E hold vs hydro shield: Lisa E hold has a strong electro aura application. It seems that strong electro applications triggers electro-charged twice for a total of 4 damage procs.
Beidou E vs hydro armor: Beidou E also has strong electro application and it procs electro-charged twice. Note that it takes a total of 10 electro-charged damage procs to take down the armor.
Fischl charged attack vs hydro armor: Fischl's charged attacks have weak aura application and it took a total of 5 shots (10 electro-charged damage procs) to take down the armor.
Barbara vs pyro armor: Barbara normal attacks have weak application and it took 4 vaporize procs to take down the armor. Note some attacks not procing vaporize (and thus not doing damage to the armor) due to internal aura application cooldown.
XQ vs pyro armor: XQ has two weak aura applications on his E + his swords apply weak hydro aura. In total it took 2 E swings + 2 touches with swords. I also did some testing with XQ ult but it was kinda inconsistent due to swords revolving around XQ also applying aura, need more testing.
Don't have footage but it is common knowledge that Kaeya's E has strong application and breaks electro armor in 2 Es, but Kaeya's ult has weak aura applications and needs 4 superconduct hits to break the armor.
Also common knowledge that Amber's charged is strong and requires 2 hits, Guoba is weak and requires 4 hits.
Pyro armor: The equivalent of 2 strong hydro
Cryo armor: The equivalent of 2 strong pyro
Hydro armor: ~10 electro-charged ticks
Electro armor: The equivalent of 2 strong cryo
By: Bobrokrot#0111 Added 12/19/2020
Evidence: Aside from geo damage, there is also a number of attacks that break Geo Armor. As far as I can tell, all of these attacks have one thing in common — they push or stagger the enemy.
Here are some clips Jean breaking Geo Armor of Geo Fatui with charged attacks and her E, and also a clip of her breaking a crystal with her E (her E and charged attacks also one-shot white iron ores). The last clip features Amber E almost one-shoting the crystal and Anemo MC last tick of E dealing significant damage to the crystal.
It is common knowledge that Overload reaction breaks Geo Armor — it can be explained by the fact that Overload explosion pushes enemies.
Claymores are well known to be effective at breaking Geo Armor. Although Jean's E pushes further away than claymore attacks, they are more effective at breaking Geo Armor. My theory is that the stagger effect also breaks Geo Armor. Claymores stagger enemies and they do so more effectively than other weapons' basic attacks.
Sword basic attacks in particular are able to break Geo Armor, although ineffective. Also note that some attacks deal more damage to armor than others, in general, final attack in normal attacks string deals the most damage.
Klee's basic attacks are effective at breaking Geo Armor and they indeed do stagger. Other catalyst users do not stagger enemies and indeed Lisa deals 0 damage to Geo Armor: https://youtu.be/a0-sSrbViUs
Significance: May significantly alter our Abyss clearing strategy. Geo and claymores are still best at breaking Geo Armor but Amber in particular with some electro for Overload can be effective at dealing with Geo Fatui since her Bunny deals massive damage to the armor (almost halves Geo Fatui armor).
Theory: INTRODUCING KAEYA'S N1 (KN1) AS A MEASURING TOOL FOR STAGGER VALUES
Evidence: Here is a clip of Kaeya hitting Geo slime's armor 140 times: https://youtu.be/40VAHBX4ABw We will postulate that Geo slime's armor has durability of 140 Keaya's N1s (KN1). Note that it actually has from 139 to 140 KN1 health. The clip above was performed with lvl 80 Keaya with lvl 1 weapon and no artifacts. To make sure that the damage itself deals no damage to the armor, here are two clips of naked Razor and Razor with lvl 77 Wolf's Gravestone and +20 feather: https://youtu.be/kMwSzxlZ1W0 https://youtu.be/OiRLK2LzAl4
From here we can calculate Razor's N1 capability to break geo armor. I'll call it stagger value from now on since evidence tells as that they are correlated. Razor's N1 ranges from 27.8 to 28.0 KN1 (plus-minus the last Kaeya's N1).
Chongyun's N1 ranges from 25.6 to 25.8 KN1 https://youtu.be/tasOZkNXbTs
Beidou's N1 ranges from 21.0 to 21.167 KN1 https://youtu.be/3uubYN2WP74
Note that Beidou's N1 and Razor's N1 stagger values correlate to my findings on their shatter values vs Cryo Abyss mage shield. I have lvl1 Razor so the result of ~0.66-0.67U of his N1 should be accurate (since the damage to shield is neglectable). Using average stagger values we can calculate Beidou's N1 shatter value = 21.1/27.9*0.66 = ~0.499 which correlates for my previous result of 0.5U. Also note that this is not the case for Chongyun. At first I assumed Chong's N1 to be 0.65U. Calculating it from stagger values it should be around 0.61U. 18 N1s is 10.98U which suggests that Chong should've had one more attack before breaking 12U shield which was not the case.
Did lvl 20 Chong deal too much damage or there is something else I did not consider?
Significance: We now might be able to measure stagger values precisely. Please contact me if you want to cooperate and make a database for all attacks in the game.
Evidence: (all of tests below were conducted with lvl1 weapons and only an upgraded flower among artifacts)
Note 1: Geo also Shatter Cryo Abyss mage shield thus Geo is able to break the shield above water.
Note 2: on Swirl on Crystallize reaction you can clearly see Hydro symbol appearing above mage. Also note that Crystallize reaction creates Hydro crystals instead of Cryo.
Note 3: Ningguang basic attacks consume 0.5U with Crystallize. 12 attacks against 12U shield is equal to 1U per attack, so we expect Shatter of Ninguang basic attacks to have a total value of 0.5U (on Shatter values I'll expand in a separate submission). With 0.5U per attack from Shatters we would expect 24 Ningguang basic attacks to break the sheld on water instead of 23. The reason for this difference is that, first, Ninguang basic attacks actually Shatter 2 times per attack (you can see the animation for each if you attack with Ning up close; also see Shatter submission) and that a total of 46 Shatter of lvl 20 character deal a total of 5474 damage. For a lvl 81 Hydro Abyss mage my estimation for 0.4U of shield is around 5-6k (see https://docs.google.com/spreadsheets/d/167gv0GWLu5HFLGCXZW3mBY0S2nimPv3dm5mGsxSiJME/edit#gid=0)
Significance: Don't use Geo or Anemo to break Cryo Abyss mage shields on water.
By: Bobrokrot#0111 Added 2/4/2021
Theory: Each Electro-charged tick consumes 0.4U. Abyss mage shields have 12GU HP (regardless of the reactions), Fatui armor has 4U HP.
Evidence: The detailed explanation with calculations can be found here: https://docs.google.com/document/d/1WvF5MTMMdCCmfb90uJ2EXzTNfjGs_sZuaRDmgUgjL_U/edit?usp=sharing
By: Iron IV#3832 and sexyeboy69#3215 Added: 04/05/2021
Theory: Childe's shield is broken through poise damage rather than raw damage.
Evidence: Childe has a separate poise value when shielded and unshielded. The hit that breaks his shield has no hitlag. The number of hits it takes to break his shield is unaffected by damage.
Significance: Prioritize stagger over damage when hitting Childe's shield.
By: Yukarix#6534, Ayzel#7399, Bobrokrot#0111, srl#2712 Added: 6/5/2021 Discussion
Finding: Pyro and cryo appear to be equally effective in terms of efficiency at depleting the shield of an Abyss Lector. This finding does not account for whether there are more pyro or cryo units that have the ability to apply their respective elements at a fast rate. It only accounts for the fact that 1GU of cryo deals the same damage to the Abyss Lector as 1GU of pyro.
Damage dealt (artifact/weapon quality) does not seem to matter with an exception of Ganyu. For Ganyu, it seems like with no artifacts & level 1 weapon, she takes the same amount of hits as Bennett, but starts to take less hits with a leveled weapon and artifacts. Units used to test pyro were Bennett & Xiangling. Units used to test cryo were Kaeya & Ganyu & Rosaria.
Significance: If you have pyro or cryo units that have fast elemental application, using one over another will not matter. Both should produce the same results given the same speed of elemental application.
Bennett with level 1 weapon: took 17 hits with sliver of shield health remaining removed by 18th hit
Bennett with level 90 aquila: took 17 hits with sliver of shield health remaining removed by 18th hit
Bennett with level 90 aquila and high quality artifacts: still took 17 hits with sliver of shield health remaining removed by 18th hit
Ganyu lvl 1 weapon: took 17 charged shot w/ blooms + last sliver removed by 18th hit
Ganyu level 1 weapon and very good artifacts: took 16 charged shot w/ bloom + last sliver removed by 17th hit
Ganyu level 90 weapon and very good artifacts: took 13 charged shot w/ bloom + last sliver removed by 14th hit
By: vibe checker#5502 Added: 6/5/2021 Discussion
Finding: Damage to enemy shields is affected by three main formulas, which are summed for final damage: Reaction Cost, Damage Cost and Poise Damage Cost. All info was accumulated from the wiki and individual testing
Evidence: There are pages on the wiki that already detail this information, however I created a google document which aims to compile it all into one source which is easy to digest. All references are included in the document.