Once you take down Noth and Heigan, the only boss left in the Plague Quarter is Loatheb. If you can defeat Loatheb, you will earn the Sludge Belcher (five-mana, 3/5 taunt with a Deathrattle that summons a 1/2 Slime taunt) and complete the wing, which rewards you with Loatheb (five-mana Legendary 5/5, with a Battlecry that makes enemy spells cost five more next turn). At first glance Loatheb may seem a bit overwhelming. While most bosses have a hero power that you must figure out a strategy against, that isn’t the case with Loatheb.
The big shock when you first play against Loatheb is that he has 75 health. Many decks are not built to dish out that kind of damage, so you may wonder how you’re supposed to take down this apparent monster. There are two cards that Loatheb has several copies of that help tremendously in your effort to take him out. Deathbloom is a four-mana card that deals five damage to a minion and summons a Spore for Loatheb. Sporeburst is a one-mana card that deals one damage to all enemy minions and summons a Spore. Spore minions are 0/1 and have a Deathrattle that gives all enemy minions (your minions) +8 Attack. Yes, you read that correctly, the Spore significantly buffs all of your minions currently in play.
To take advantage of the massive buff, you need to make sure you have the proper minions in play. It’s not hard for Loatheb to inflict three or four points of damage to all of your minions between his various Spore-spawning cards and whatever minions he already has in play. If you have a lot of minions with two or three health, they probably won’t survive long enough to take advantage of the Spore buff. However, you need to establish board control in order to force Loatheb to use these cards and summon the Spores.
Your best course of action is to have an aggro deck composed of a good number of low-mana minions that will give you an early advantage. Once you’ve established board control, you need to have minions available that can take advantage of the Spore buff and stay alive long enough to make it work in your favor. If you can fill the board with minions, and at least a few of them have more than two or three health, you should have at least a few left to attack with by the time you kill the Spores and buff your minions.
Let’s take a closer look at how this works. If you have three minions that survive after killing off all of the Spores, that’s 24 damage not counting whatever Attack value the minions had before the buff. In a single turn you’re inflicting at least 24 damage with minimal effort. That’s one-third of Loatheb’s health in just one turn. Now imagine if you had five minions survive that all had at least two Attack. That’s 50 points of damage you’ll be inflicting that turn. As you can see, it doesn’t take long for the damage to add up.
Loatheb’s hero power deals three damage to your hero. Think of it like the Hunter hero power with one additional point of damage. It’s not something that your minions need to worry about, and as long as you have enough minions in play to take advantage of the Spore buff, Loatheb’s hero power really doesn’t factor into this match.
You need to watch out for Loatheb’s Faceless Manipulator cards (he has at least two), in addition to his taunt cards (Fan Creeper). You should also take down the Flesheating Ghoul and Shade of Naxxramas minions as soon as you can. With this strategy you avoid having to deal with buffed up minions, while waiting for Spores so you can buff up your side of the board and inflict significant damage to Loatheb.