Hearthpwn

I've been playing a lot with this deck since the release, so would like to present updated and refined post-balance patch Unholy Aggro Death Knight list that is absolutely filthy in the current standard meta.

What has changed since the patch?

Unholy received buff to Battlefield Necromancer, which is an extremely strong 2 drop now. However, nerfs to Miracle COC Rogue and overall meta shake-up are what benefited this archetype immensely. The fact that you are not facing 0 mana Wildpaw Gnoll in basically 50% of your matches has made a huge change. Moreover, current Unholy Death Knight is surprisingly strong against aggressive tempo decks (e.g. Pure Paladin, Imp Warlock) that also became stronger and more popular after the balance changes.

Short overview:

The logic and win condition of the deck has not changed. The difference is that it is working way more consistently. Strong one and two drops followed by various small synergies lead you to board dominance and mid/late-game win conditions with Grave Strength and Lord Marrowgar. It is also clear that this type of aggro version is far more superior than other slower and greedier variants of the Unholy DK.

Mulligan and strategy:

• Body Bagger, Irondeep Trogg and Arms Dealer are the strongest 1 drops, so you almost always keep them on mulligan. One drop followed by Battlefield Necromancer or Vrykul Necrolyte on turn two is the big early power play, especially when going first.
• Plague Strike is another key card in almost any match-up, especially against decks that have same game plan and fight for the board from the very start of the match. It is even great against some slower decks (such as Big Mage and Blood Death Knight) that play Far Watch Post.
• Blightfang is another gamebreaker against aggressive decks such as Imp Warlock or Pure Paladin. It absolutely slays against these two decks.
• Hawkstrider Rancher is a central tool that can be kept on mulligan, according to the match-up and other cards you have.

Tech choices:

• Some lists run Peasant that I think is not good enough. It is not bad in mid-late game, especially if you combo with Hawkstrider Rancher. On the other hand, a 2/1 no-tag minion is not a good turn 1 play and currently deck does not seem to have a problem of card draw/generation without it.
• Same with Banshee, Nerubian Egg or Bonedigger Geist. They are not good enough.
• Most of the lists run Amalgam of the Deep instead of Necrotic Mortician. They are quite similar, but I prefer the latter for several reasons. While none of these cards are optimal on turn two, Necrotic Mortician gets activated without requirement of an undead minion on board and also offers you game changing unholy cards such as Grave Strength, Plague Strike, Blightfang, Army of the Dead or The Scourge. In addition to this, you can find Lord Marrowgar more often from him than from Amalgam.

Update (07/02/2023):

A couple of thoughts and updates after more games in Diamond/Legend ranks:

• Triple Unholy is either a tier 1, or at least a very strong tier 2 deck.
• Other Death Knights and Mages are hard match-ups. Rainbow and Blood Death Knights are beatable. Same with Aggro Frost and Big Spell Mages. Frost Death Knight is the ultimate worst one, unless they draw really badly it is nearly impossible to deal with several Frostwyrm's Fury from turns 6-7 (sometimes even earlier with other cards such as Might of Menethil).
• In current meta, Irondeep Trogg looks like the worst card from the list and has to be replaced. I had to reassess my initial thoughts on Peasant. It has surprisingly good stats on HSreplay and is apparently the best replacement for Irondeep Trogg. So Troggs out, Peasants in.

Return to Naxxramas mini-set update (16/02/2023):

Construct Quarter looks strong enough to give it a try. I personally still think  location fits Frost Death Knight deck best, but it should also work well in Unholy Death Knight.

There are several cards in the current deck that can make way for Construct Quarter. Cutting one copy of Famished Fool and/or School Teacher is under consideration. However, I guess without two Famished Fools deck will simply lack consistent card draw. I don't like cutting School Teacher as well, as it is one of the few proactive 4 drops of the deck with an additional 1-mana token + discovered spell. Therefore, I think cutting two drops might be the best idea, that is Necrotic Mortician in this list, and Amalgam of the Deep in other popular lists.

It should be noted that this is just a preliminary thought. At the end of the day, after enough play-testing list with location might end up being slightly worse than the previous one.