Death Knight Detailed Mechanics

by **Kuren** » 22 Oct 2010, 04:31

Background

This thread is to document the fine details of Death Knight mechanics. While most Death Knights may not care about such details, theorycrafters and addon authors will be interested in it. I'm going to post my initial findings from working on the Blood Shield Tracker but we should slowly expand this information as we go along. To add to the information, please provide me the detailed data and the testing and calculations behind it. I will provide links or some reference to all results. If you believe you find any errors or believe that something isn't clear, please let me know.

Death Strike

Death Strike will heal the Death Knight for 20% of the damage in the last five seconds or a minimum of 7% of the current maximum health. The Death Strike heal itself is affected by all healing modifiers. The minimum DPS heal is not affected by healing modifiers of any sort and is purely based upon 7% of the current maximum health.

Code: Select all: MinimumDSHeal = CurrentMaximumHealth * 0.07 DeathStrikeHeal = max(DamageInLastFiveSeconds * 0.20 * (1 + (PointsInImpDS * 0.15)), MinimumDSHeal)

Any other healing modifiers are applied after the DeathStrikeHeal calculation above. Therefore, effects like ICC healing buff, Mortal Strike, Guardian Spirit, etc. are applied after the basic calculation.

Some details I've noticed while reading combat logs for it:

The damage in the last five seconds doesn't include absorbs. Whether a full absorb or a partial absorb, it isn't included in the recent damage taken.
The heal doesn't always match the total damage in the last five seconds based on the combat log. It is probably due to issues with latency plus the fact it is done server-side.
The heal is affected by any and all heal absorption or reduction effects (i.e., Mortal Strike, Necrotic Strike, etc.).

Interaction with Vampiric Blood
Vampiric Blood increases the healing done by Death Strike. The modifier is dependent on whether it is glyphed or not.

Blood Shield

The Blood Shield is applied after a successful Death Strike. The Blood Shield tooltip says it is based upon the Death Strike heal but that is only somewhat true. The basis for the amount is derived from the last five seconds worth of damage modified by the Improved Death Strike talent. Therefore, the formula used is below and is similar to the Death Strike Heal above:

Code: Select all: MinimumDSHeal = CurrentMaximumHealth * 0.07 BloodShieldBasis = max(DamageInLastFiveSeconds * 0.20 * (1 + (PointsInImpDS * 0.15)), MinimumDSHeal)

As for Death Strike, if that basis is less than the Death Strike minimum value (i.e., 7% of current maximum health) then the 7% value will be used instead of the basis calculated above.

Effects like Mortal Strike or the ICC healing buff do not affect this number. For example, if Mortal Strike is on you and you gain a Blood Shield, you will get the full Blood Shield amount even though the Death Strike heal will be for half of the expected amount.

The Blood Shield will be a straight percentage of that value based upon the mastery. The tooltip shows a rounded integer; however, the actual value is used in calculating the shield value.

Code: Select all: BloodShieldPercent = MasteryRating * 6.25 / 100

You can then take that amount and calculate the Blood Shield value:

Code: Select all: BloodShieldMaxValue = max(DamageInLastFiveSeconds * 0.20 * (1 + (PointsInImpDS * 0.15)), MinimumDSHeal) * MasteryRating * 6.25 / 100

Blood Shields do not stack. If you cast Death Strike while a Blood Shield is still active, you will gain a new Blood Shield based on the last five seconds of damage. It starts at the maximum value, recalculated from the last five seconds worth of damage.

Interaction with Vampiric Blood

The minimum Blood Shield is tied to the Death Strike minimum heal value; therefore it is affected by the non-glyphed Vampiric Blood. If you are in ICC, keep in mind that using non-glyphed Vampiric Blood provides 15% more health but that is affected by the ICC buff itself. You will actually get an additional 19.5% health (i.e., 15*0.3=19.5). The Blood Shield amount is not affected by healing increase from Vampiric Blood.

Bloodworms

Coming soon.

by **Gravity** » 22 Oct 2010, 06:45

Re DS, I think the ICC +heal aura is effecting the self-heal element, if I recall right. Just mentioning it quickly; if you can ratify I can find the test source it was on EJ iirc.

by **Kuren** » 22 Oct 2010, 06:52

Yes, the Death Strike heal is affected by the ICC buff. It's the Blood Shield that wasn't affected by that part of the ICC buff.

by **Perditio** » 22 Oct 2010, 09:46

So just to clarify, does that mean the Blood Shield is actually de-coupled from the actual healing done by DS, and instead does it's own calculation of the last 5sec of damage (and thus won't take into account things like VB and GS)?

Also, I think you have a little typo: "The minimum DPS heal is not affected by healing modifiers of any sort and is purely based upon 10% of the current maximum health." Should read "minimum DS heal".

by **Satorri** » 22 Oct 2010, 11:09

Two things:
The Blood Shield applies like several other similar abilities that offer a % of something else. The source (DS heal in this case) can be buffed, and vary, but the shield does not double-dip, so the shield will scale with the +heal buff from ICC, but it will not *also* get the +absorb buff from the buff. That would be pretty insane if it did, ha ha.

Kuren, maybe you can speak to this. I heard talk that DS worked on the full value of partial absorbs, but it didn't not work on full absorbs. So, if you fully absorbed a hit it might as well have been avoided for DS's heal math, but if you got hit for 15k and absorbed 5k of that, the damage taken equation would include the full 15k hit. Mind you, this was just semi-idle chatter, so I can guess that it may have just been a function of a bad Operator game, but it didn't sound like it couldn't happen. Can you settle that conclusively?

by **Kuren** » 22 Oct 2010, 20:43

The DS heal is affected by the ICC buff but I'm saying that the Blood Shield isn't affected by the ICC healing buff nor is the ICC healing buff on the DS included. It could be that my description above isn't clear on that?

As an example from my soloing one of the valkyrs in ICC just to check the numbers:

I had a DS heal for 14415. The Blood Shield was for 10918. The ICC buff is 30% so the DS heal would have been:

14415/1.3=11088.

Now that the ICC buff has been taken out, we can verify the BS value by multiplying it by my master times the 6.25 and divided by 100:

11088*15.75498008728*6.25/100=10918

The next hit was for 1252 with 10918 absorbed so that confirms that the server also used that same value.

I don't see that full absorbs and partial absorbs are treated any differently. The DS heal is always based on some combination of purely the recent damage taken. Blood Shield Tracker is getting incredibly accurate on figuring that stuff out and I don't include an absorbs in those calculations.

by **Perditio** » 22 Oct 2010, 21:32

That's actually interesting that it doesn't take into account the ICC heal buff when working out Blood Shield; does this mean it doesn't take into account other heal% increasing effects such as GS? From the wording of the tooltip I would've thought that the shield was based directly off the amount healed. If this isn't the case, Blood Shield could still be quite useful on bosses that have a MS debuff - even if your direct healing is reduced, you would still get the benefit of the full Shield.

On the flip side it also means you can't place up super-charged shields by timing a few DSs to fire when you have VB or GS active.

by **Kuren** » 22 Oct 2010, 21:56

Did you read my post? I have to ask because if so, I haven't been clear but I stated it above. The healing modifiers, other than the Imp DS, aren't included. Which is nice since things like MS, etc. would make our Blood Shield irrelevant. Those DK Essence adds spawned by the valkyrs in the ICC Upper Spire have a Necrotic Strike that reduces healing by 15000. That pretty much kills DS but you still get a Blood Shield based on recent damage taken.

Acronyms can be dangerous. :-)

I'm assuming GS = Guardian Spirit. I didn't specifically check it but given that every other healing modifier I've seen follows the rules above, I'm guessing it would be the same. I'll try to test it some time.

by **Perditio** » 22 Oct 2010, 22:12

Yeah, it's clear to me now, I just wanted a bit of clarification due to what was a bit of ambiguous wording (imo). I initially took what you said to mean that Blood Shield doesn't double-dip into the healing/absorb ICC buff - as it seems Satorri took it to mean.

by **Kuren** » 22 Oct 2010, 23:45

Ok, I'll keep updating the original post to make it clearer.

I went and verified it. Guardian Spirit doesn't affect BS as I said. I'll probably add that to Blood Shield Tracker as that one is reasonable to have in a raid and until Blizzard provides better BS tracking (like they do for PW:S) I have to calculate everything manually.

by **Insolence** » 23 Oct 2010, 17:11

So uh.....

ICC Healing affects Death Strike healing.

ICC Absorb does not affect Blood Shield absorb?

by **Kuren** » 23 Oct 2010, 19:19

Yes, the Blood Shield is interesting in that it doesn't vary based upon healing/absorption modifiers. I assume it was done so Blood Shield doesn't move to extremes. If all of those buffs affected it, it could get better than block since those effects would amplify its power. On the other side if negative healing/absorption modifiers affected it, it could completely negate the power of Blood Shield. In raiding we tend to mostly just encounter the positive healing modifiers though so I can see where it is disappointing. To use the example above though, Guardian Spirit doesn't make you block better.

by **Insolence** » 23 Oct 2010, 19:53

Yeah I guess its because with the +30% Healing to Death Strike you already gained 30% increased Absorb on Blood Shield either way, so having it affected by both would increase it to 60% bonus.

by **Kuren** » 23 Oct 2010, 20:24

No, I'm saying that in order to calculate the Blood Shield amount from the Death Strike heal, you factor out the 30% ICC buff that went into it. There is no part of the 30% ICC buff in the Blood Shield amount--direct or indirect. I thought I've been clear on that part.

by **Insolence** » 23 Oct 2010, 20:27

Ok ok re-cap:

ICC Buff increases Death Strike Healing by 30%, but that 30% is not also added to Blood Shield? That sucks.