I've not read online, I do not pretend to know which stats Mr. Robot says you should respec for, and I've never built my toon based solely on any one or multiple websites. This guide is to explain how the Blood Death Knight works and the importance of thinking for yourself in the googling era. I have used websites as a reference in the past, but over the years I've developed what I believe to be the sturdiest of builds, both extremely capable of taking absurd damage and delivering acceptable damage.
**Some of this stuff might seem elementary, but I've decided to include it to be thorough.
Addons are generally up to the player, but I would recommend these two for anyone taking thier Blood DK seriously:
DocDebugRunes and BloodShieldTracker. The first is just a simple display of your runes, runic power, disease timer, and blood shield. Normally I'll have everything turned off except the runes and runic power, since the addon is outdated and is prone to fucking up the other stuff. The latter addon is essential to any progression-level Blood DK unless you fancy looking at 3 different parts of your screen at once. I will explain its necessity in the "That blood shield tho LOL" section. Tidy Plates: Threat Plates are also a big help, and can be automatically or manually configred.
The Proving Grounds are a good way to get comfortable with any class or rotation, but there is something else that I promise will make you a rock-solid tank, no matter which class it is. Begin with equipping god-awful gear, get yourself a decent healer, and some high-end dps that loves to pull things before you're ready. Go into a dungeon, and move through it as quickly as you can, while holding all of the aggro. If your dps pulls, do not hit them, just pick it all up. Do this all without your cooldowns, and then pull more than you think your healer can handle, and begin to use your cooldowns. If you're really feeling bold, ask your dps and heals to slip into some greens and blues as well. If you're doing this as a death knight, you will find your runes don't always line up with the inconsistent pulls (fucking dps, amirite?.) This is something you need to get used to, and find ways around.
In an effort to not turn this into a Tanking 101 guide, let's get on with the show:
I. That blood shield tho LOL
Yes, as anyone will tell you Mastery is a Death Knight's best friend. We have no shield, no way to soften blows that aren't completely mitigated. Instead, we've been given a semi-active mitigation similar to a priest shield, but one that DOES NOT ABSORB MAGIC. How well you manage your blood shield will either make or break you as a blood death knight.
There are two factors which determine the strength of your blood shield: Scent of Blood and Damage taken in the last 5 seconds. This is why you healers see my health shoot down and then pop up very quickly. I won't copy/paste the Death Strike or Scent of Blood tooltips into this guide, you can read them for yourselves, but the main idea with both is the more the better. The more damage, the more stacks of SoB, the better your shield. There's a reason I get those 1.3 mil shields in one death strike, folks. Blood Shield Tracker is a simple addon that displays your SOB stacks and estimates how much physical damage your Blood Shield will shield you for.
Sometimes it's better not to attack, and wait to be hit. This may seem counterintuitive at times, because you rely on your runes to grab threat from the OT during a swap as well as to heal yourself. Omen Threat Meter is recommended, but not required, as there are unit frames that display threat. Be conservative with your runes, do not get stuck in a constant rotation unless it is necessary, because that big hit is coming. I know this because....
II. Excitement? We've got tons of 'OH SHIT' moments!
What happens when you take away a tank's shield, make avoidance a secondary stat, and focus on that class' self healing abilities? You get "OH SHIT" moments. They will happen with this class. You cannot avoid them. Just ask Riggnaros. Thankfully, Luminatus will give you the tools you need to compensate with this sudden loss of health.
Your first line of defense is always your Death Strike. You should know when to expect heavy damage loads (lots of mobs in a dungeon, raid boss (read buffs, debuffs, stacks, etc.) There's a reason they give you two of them. With 1 Death Strike, your blood runes, and Scent of Blood (read spellbook if you dunno), you will have plenty to keep you using Rune Strike. Save those other two Frost/Unholy (or death) runes for when your health dips below 50%.
Blood DK's like stamina more than other tanks for various reasons. One is because it improves our base DS heal, resulting in a higher base blood shield. This is great, because 300k blood shield doesn't do dick, as you will find out. But I think the more important reason for not forgetting about stamina (I'm not saying gem straight stam, but hybrid gems aren't out of the question) is to better deal with these "Oh shit" moments. If you get an unlucky set of unmitigated attacks, your health will drop into the danger zone, but you can broaden that zone with increased stamina. It might give you the second or two you need to get your runes up to Death Strike.
The best macro I've ever used (and I'm pretty sure the only one) is the Raise Dead + Death Pact macro. With two keystrokes, I can heal myself for 50% or 70% of my health (depending if Vampiric Blood is in use.) It's a great last resort if you get beat on and don't have runes up.
Obviously, if Vampiric Blood is available, you should use it before any of your self-healing abilities during one of these moments. It works with Rune Tap, Death Pact, and Death Strike.
III. Why your damage is shit, and what you can and can't do about it:
I won't tell you how to build your character, feel free to armory mine for some pointers. I will say this, though: Death Knights are a balancing act, what you give up in damage you (should) gain in survivability. Here's why:
Mastery is designed to smooth out the constant damage being dealt by a raid boss or group of enemies. It mitigates hits that would otherwise cause you to lose health. Dodge and parry on the other hand is like a gamble, and should be treated in this way: Maybe with enough rating in dodge or parry, your blood shields will last longer. That is it. It should not be treated as a primary survival mechanism. This is because we do not have shields to soak some of the damage we take when we fail to dodge or parry an attack.
Since the Riposte changes you will receive critical strike rating equal to 75% of dodge and parry. Crit does not benefit us in any other significant way. Do not gem crit, gem parry instead.
Dodge and Parry also benefit the Blood Death Knight in another way: They have a chance to grant us 10 runic power. Read the Scent of Blood tooltip for an explanation of how this works.
I will not give you a magic number where you should stop gaining mastery and start gaining avoidance, though it should come in that order. It's a matter of what your comfortable with. Consider how much strain you want to put on your healers while thinking about this as well. You see things like "DK avoidance build" or "DK mastery build" but I am suggesting that you BALANCE how much damage you think you can handle (+/- Mastery, and to an extent Stamina) with how much damage is required of you by the raid (+/- avoidance). It is perfectly possible for a DK with 30% avoidance to do just fine in heroic raids, as long as he has put that lost avoidance in mastery (albeit his damage will be atrocious.)
"BUT LUMI, WHY ARE YOU ALL PARRY AND NO DODGE?"
The parry-haste effect (if an attack is parried, it reduces the auto-attack swing timer by 1/2) still exists for players. Dodge has no such mechanic. This means more damage (since Riposte isn't affected by diminishing returns, this equals out) and more importantly, MORE SCENT OF BLOOD STACKS (because you're attacking faster.)
IV. Stayin' Alive (ah, ah , ah, ah...)
If it were not for the necessary use of cooldowns, tanking would be a very dull position to fill indeed. Fortunately, the Blood DK takes it one step further, and makes the cooldowns in their toolbox not only necessary, but damned fun.
Please remember, though, that to know one's enemy is to defeat him, and being able to predict enemy damage (it's possible, just think about it) allows you a window of time to prepare for the freight train headed your way. Is the train made from solid elementium? Or is it more of a misty magical train? These questions will help you pick the right answer when it comes to cooldowns.
Bone Shield: Use on cooldown. Becomes even more righteous with the legendary meta.
Vampiric Blood: This should be your go-to cooldown. If you've just taken damage and want to make the most of your blood shield, make sure to use this BEFORE using death strike to recover health.
Dancing Rune Weapon: My favorite. Parry rating and increased damage. Remains fixed on the target you've casted it on until that target is dead. Use this for physical melee attacks (or if the boss is applying a debuff, and you want to mitigate more of his auto attacks.) You can also use it for more threat, and quite affectively once it's glyphed. If you're a complete professional you will be interested to know that it also duplicates your interrupt. You can interrupt two targets simultaneously if you're good enough.
Anti-magic Shell: Sort of a no-brainer on this one. So many people forget to use it, though. Pop this while a boss is casting or once you've accumulated a shit-ton of magic damage debuff stacks. This charges your runic power, so use in a group of mobs with casters if you're starving for threat or damage!
Icebound Fortitude: Last resort. Remember that you have Will of the Necropolis (25% reduced damage when falling below 35% health), so if a Death Strike is available, use that instead. This can be used for magic damage or physical damage, and under normal circumstances doesn't need to be used in combination with any other cooldown. If you need to soak one shot of super heavy damage, consider glyphing it. (this helped on madness of deathwing, with the glyph it is solo tankable)
SINCE 5.2 HASTE IS GARBAGE FOR BLOOD DK I WILL FIGHT ANYBODY THAT SAYS OTHERWISE. YES, IT WAS VIABLE, IT IS NOT ANYMORE. STOP LIVING IN THE PAST. CRIT IS YOUR DAMAGE STAT #dealwithitgif.
If there are any questions regarding glyphs, talents, or anything else Blood DK, please post them on this forum or contact Luminatus in game. Cheers.