Boss specific recommendations and strategy:Raid Bosses
Tier 1 (15)
Infected Claws - You take this talent when playing the Night Fae build, or if you want to prepare some big AoE damage for your Death and Decay windows when using Bursting Sores. However, it is typically not worth taking without Bursting Sores in Mythic Plus. If you are playing the Night Fae build, then you will be taking this talent most of the time over the other two options in this row.
All Will Serve - This is the go-to talent for almost all Single target scenarios. The Skeletal Archer it summons does good single target damage, although, in heavy cleave/AOE scenarios, All Will Serve is not very competitive (it deals only a minor amount of cleave damage). It's ranged, so it keeps a good uptime on your primary target and performs better than Clawing Shadows on Single target fights. However, the archer's movement can be very inconsistent if the boss moves vast distances or between platforms. It will often have very poor uptime in these scenarios like; Sire Denathrius and Sylvanas Windrunner are two great examples of fights you would not want to use this talent on.
Clawing Shadows - A solid choice for multiple situations. It makes your Scourge Strike usable from up to 30 yards away, and also makes it 100% Shadow Damage instead of a 50% Physical / 50% Shadow mix. This means it benefits greatly from your Mastery: Dreadblade and makes your Scourge Strike do more damage overall (the physical damage element of Scourge Strike is mitigated by the armour of the boss). While this talent is generally not better than All Will Serve on Single target, it does become better when you frequently need to move away from the boss due to mechanics.
The damage you miss from lack of melee uptime and Scourge Strike uses, is greater than the damage you will gain from All Will Serve. So if there is a fight where you need to move away from melee range often, this talent will be the better option. Another reason to take Clawing Shadows is when the Skeletal Archer from All Will Serve has poor uptime due to boss design, as discussed above. In AOE/cleave scenarios this talent is very good as it does a lot of damage in your Death and Decay windows, because of its 100% Shadow damage (which again is not mitigated by armour and scales with Mastery: Dreadblade), so you will want to use Clawing Shadows in most AOE situations. However, it is capped at 5 targets, so Infected Claws will be more effective with the more targets you are fighting when used in conjunction with Bursting Sore or when using the Night Fae build.
Tier 2 (25)
Bursting Sores - You want to take this talent for very big pulls in Mythic Plus or with consistent burst AOE situations with a large number of targets. You will always pair this talent with Infected Claws so your pet can spread Festering Wounds across all the targets it cleaves during Dark Transformation. Bursting Sores also does Shadow Damage, so it scales very well with your Mastery: Dreadblade. It does not have much use outside of these scenarios, so you will most likely only see the use of this talent in MDI style pulls/dungeon runs. The build also requires the rest of your group to allow your pet to stack up Festering Wounds to get the full value of this talent. Another talent that falls hand in hand with Bursting Sores is Pestilent Pustules, which we will discuss soon.
Ebon Fever - This talent is severely underwhelming and has been bad since the class changes in the Shadowlands pre-patch. With the change to Outbreak (no longer reapplying Virulent Plague every second during the 5 second Outbreak debuff), it has lost a lot of damage. With the other options on this talent row performing far better than this one, it has not seen play since and is not worth considering.
Unholy Blight - is the default choice for almost every situation; it’s versatile and great for AOE and single target scenarios. Not only does it give your Apocalypse Ghouls, Dark Transformation, and Army of the Dead an additional 12% damage at 4 stacks, but it also applies and reapplies Virulent Plague every second for 6 seconds to all targets within 10 yards of you. Additionally, you can pre-cast it 2 seconds before a set of enemies appear to apply Virulent Plague to them instantly and still have enough time for it to apply 4 stacks of the pet damage debuff. This will enable you to use Epidemic immediately, without using Outbreak on them after they have spawned to apply Virulent Plague. This can also work very well on mass AOE situations as it increases the damage of your Dark Transformation and its cleave damage from Claw casts. This is the best option overall and will be used in almost every scenario.
Raiding: Unholy Blight
Tier 3 (30)
Grip of the Dead - While its use is a niche, it can be very good if you need to kite or slow down a set of targets. This can be incredibly useful in fights such as Kel’Thuzad because you can slow the Frostbound Devoted. This makes them easier for your raid to control and deal with. Consider taking this talent if you do not require the other two in this row, and some adds need to be slowed and controlled (It does not work against bosses or targets immune to crowd control).
Death’s Reach - One of the main strengths of a Death Knights is their ability to Death Grip adds into specific positions, which can make an encounter significantly easier to overcome for your raid team. This talent just makes you able to do your job a little better by allowing you to Death Grip targets to you from a further distance. This was especially useful in Castle Nathria on multiple encounters, such as Stone Legion Generals, where you would want the extra Death Grip range to grip the Stone Legion Skirmisher’s into the boss. And in Sanctum of Domination on Soulrender Dormazain, where you could grip the Mawsworn Agonizers that were further away from the rest, making it much easier to kill them off quickly for your raid team. Overall, this talent is useful and my default choice for most encounters.
Asphyxiate - You pretty much take this talent when you need a stun. I recommend taking this talent in Mythic Plus as having a ranged stun is very useful and is almost mandatory for high-level keys.
Tier 4 (35)
Pestilent Pustules - If you consistently do big pulls and want the most effective Death and Decay windows when playing with Bursting Sores and Infected Claws, you might want to pick this talent. With a lot of targets, you get enough Runic Corruption procs to give you an almost endless supply of runes, which in turn allows you to keep popping Festering Wounds with your Scourge Strike during Death and Decay. Often in Death and Decay windows, you will run out of runes and need to cast Epidemic a couple of times to proc Runic Corruption; however, this talent mitigates that issue. This talent is best when used with the Infected Claws & Bursting Sores build or when Soul Reaper loses a lot of its value/is not usable. An example of this would be on Sylvanas Windrunner, where you cannot get any damage out of Soul Reaper on the boss, as she never reaches <35% health, so you take Pestilent Pustules instead.
Harbinger of Doom - This talent is extremely sub-par and very rarely provides you with any noticeable value. On average, it will give you an additional 0.5 procs of Sudden Doom per minute, which is very bad if not completely unnoticeable. When compared to Pestilent Pustules and Soul Reaper, there is never a scenario in PvE that would warrant using this talent.
Soul Reaper - Hands down the best talent in this tier. Unholy DK has a strong execute phase when using Soul Reaper. It's very far ahead of any other option in this row. It does significant damage during the execution phase. It is also an effective tool you can use to snipe some targets with low health, do some extra damage, and give you Runic Corruption procs as well as proccing the new Harvest Time 4 set bonus. With the addition of the new Unholy Death Knight Tier Set in 9.2, you will always want to use Soul Reaper to proc the 4 set bonus Harvest Time (as long as there are targets to proc the execute effect on). You can also proc the tier set bonus Harvest Time on low HP targets while you are in your AOE burst, and then weave Soul Reaper casts in between Epidemic on a priority target within execute range while your Death and Decay is on cooldown. The only scenario where you might not use this talent is when you are not able to get the execute proc from it, such as Sylvanas Windrunner (boss never reaches <35% health).
Raiding: Soul Reaper
Tier 5 (40)
Spell Eater - This talent just makes your Anti-Magic Shell even better, allowing you to absorb even more magic damage and also increases the duration. Anti-Magic Shell makes you immune to any magic effects that would be applied to you while it is active, including ground effects. The increased duration provided by Spell Eater is super effective because it gives you an extra 5 seconds of this immunity. Consider taking this talent on fights with heavy magic damage.
Wraith Walk - One of Death Knight’s main weaknesses is mobility, so this talent gives you a bit more flexibility with movement. It can also be very handy for root effects as it breaks you out of them. I recommend this talent on most encounters as it can really help with dodging mechanics or getting somewhere quickly. A good example of where Wraith Walk is handy is on Fatescribe Roh-Kalo, a fight that often requires you to cover some distance in a short window of time, for mechanics such as Call Eternity and Grim Portent.
Death Pact - Generally not very useful, most of the time you are already very tanky as a Death Knight, so the other options are better most of the time. However, there are some niche scenarios where this talent can be very useful. A great example of this is Sludgefist, where Spell Eater is completely useless because all of the damage you take is physical. There is also not much distance to move across, making Wraith Walk not very useful either. Another problem in this fight is that all of the damage dealt to you on Sludgefist is Environmental. Death Strike does not take that damage into account, so in a rare case like these, Death Pact is worth taking and should be used as a last resort to top yourself before taking a big hit of damage (when Sludgefist would charge into a pillar for example).
Tier 6 (45)
Pestilence - Sadly, this talent performs very poorly compared to the other options in this tier. It can only apply a maximum of 10 Festering Wounds across all targets within your Death and Decay, no matter how many targets are within it, but with average size, M+ AoE pulls, it would only apply 4-6 on average. It could only be useful in the Bursting Sores build, but even then, it’s terrible in comparison to Unholy Pact.
Unholy Pact - This talent works well in AOE and Single target. It performs better than the other two options we have, making it universally the best in all situations simply because of how it performs compared to the other talents on this row (which are very badly tuned btw). A good thing to note though is that the 5% strength buff and the Hellchains effect only lasts for the original 18 seconds of Dark Transformation, meaning that the Deadliest Coil legendary effect will not extend the Unholy Pact buff.
Defile - This essentially makes Death and Decay do increased damage and have a shorter cooldown. However, Death and Decay does very little damage, and the damage buff isn’t enough to make this talent worth taking.
That said, it does have a unique synergy with Night Fae as it makes your Death’s Due a 20-second cooldown and gains significant value when paired with the Night Fae Covenant Legendary Rampant Transference. If played with Rampant Transference, you can maintain your Death’s Due stacks permanently throughout an entire encounter. This can be a viable talent with this particular build (You will also want to use the Death’s Certainty legendary over Deadliest Coil if you are using this build, but I will go over this build more in the Night Fae section later on in this guide).
Raiding: Unholy Pact
Mythic+: Unholy Pact
Tier 7 (50)
Army of the Damned - This is the go-to talent for almost every situation. It reduces the cooldown of one of the best abilities in your toolkit, Army of the Dead. This will make your Army of the Dead have an average cooldown of 3.5 to 4 minutes, depending on boss uptime and the legendary you are using. This will enable you to cast Army of the Dead twice in almost all encounters in the Sanctum of Domination.
The legendary effect Deadliest Coil will give you a lower average cooldown due to the runic power cost reduction on Death Coil compared to Frenzied Monstrosity/Death’s Certainty. However, you will still be able to get 2 full uses of Army of the Dead in a 5-minute encounter even with Frenzied Monstrosity/Death’s Certainty, as long as you don’t have really poor boss uptime. In Mythic Plus Army of the Damned is also the best as you will be using Epidemic more than Death Coil on trash packs, so your Army of the Dead cooldown will average around 3.5 to 4 minutes, again depending on uptime. This means you can use Army of the Dead once on the boss and even use it in between the bosses (there are some exceptions, however, such as the last two bosses in Halls of Atonement). In some dungeons, you may want to use Unholy Assault instead of Army of the Damned, if you are doing very big pulls that require a lot of burst AOE. These kinds of pulls are only in MDI-style dungeon runs, though.
This talent also reduces your Apocalypse cooldown by 1 second with each cast of Death Coil and Epidemic, so pairing this talent with the conduit Convocation of the Dead will make your Apocalypse cooldown line up with Dark Transformation and Unholy Blight more reliably. For the final cherry on the top for this talent, it will also make your Apocalypse and Army of the Dead summon a Magus of the Dead, very similar to the Magus of the Dead Azerite Armour trait from Battle for Azeroth, except tuned down quite a bit. Regardless, the Magus is still a nice bonus.
Summon Gargoyle - Despite what it says on the tooltip, this talent has some good synergy with the Deadliest Coil legendary effect. You will get the same damage increase from a 30 runic power Death Coil as you would from a 40 runic power Death Coil, so your Gargoyle gains 20% increased damage for each use of Death Coil, regardless of its cost. It also accounts for Death Coil casts used with a Sudden Doom proc.
However, it is under-tuned, so much so that two uses of Summon Gargoyle in a 5-minute fight is roughly 0.9% worse than a single use of Army of the Dead. So, picking this talent over Army of the Damned is going to be a massive downgrade as you are technically denying yourself a second use of Army of the Dead. That is not even including the additional cooldown reduction of Apocalypse and the Magus of the Dead gained from Army of the Damned, which is an additional 4.3% DPS as well. If you’re killing a boss in around 2 minutes, where you will get no second use of Army of the Dead or second use of Summon Gargoyle, then this talent is technically better than Army of the Damned. However, Unholy Assault would then be picked instead, as it is better than Summon Gargoyle by around 2.1%.
Unholy Assault - This talent saw some use in Castle Nathria in very short fights, usually on the earlier bosses such as Shriekwing and Huntsman Altimor, that would last around 2 minutes in a well-suited group. However, with the additional cooldown reduction on Apocalypse from Convocation of the Dead having such great synergy with Army of the Damned, the gap is not as big as it used to be. I will say, though, that this talent is still worth taking in very short encounters that are around 2 minutes or so. In Mythic Plus this talent can also pair very well with the Infected Claws + Bursting Sores build, as it applies 4 extra Festering Wounds on your main target and gives you a nice 20% haste buff during your Death and Decay window. However, you will default to Army of the Damned most of the time even with the Mythic Plus build. The only time you will take Unholy Assault over Army of the Damned is in MDI style pulls. In those dungeons, you will be doing very big pulls that require a lot of burst AOE, making Unholy Assault an ideal talent due to its short cooldown and burst potential.