This article is about the original 40-man version of Thaddius introduced in Patch 1.11. For the 10 and 25-man versions of the raid boss introduced in Wrath of the Lich King, see Thaddius.

Somewhere deep inside the cursed necropolis Naxxramas...

Your raid cleared out the last group of monsters, and the only thing left are the two gates at the very end of the room. While the rest of your group drinks, heals up, and resurrects any players who fell during the last skirmish, you carefully approach the sealed doors. Suddenly the mighty gates fly open. A vast laboratory filled with all kinds of strange machinery lies before you, electric discharges and lightning painting the walls with jagged shadows. In the center of the room, you behold a gigantic creature unlike anything you (or any other player) has ever seen before. Even though you know you should be trying to rally your raid you can't help but stare at this monstrosity. As your group falls into disarray and scatters, caught unaware and slaughtered one by one by the two gruesome wights that descended from platforms higher up in the room, you wonder to yourself what kind of twisted nightmare spawned this monster.

Thaddius is a boss in Naxxramas. The theme of this boss is similar to that of Frankenstein's Monster, creating something akin to an Abomination in that it is sewn together of human parts, but also part machinery.

General Information

Attacks and Abilities

Thaddius has around 6.7 million HP according to SWStats taken of a kill.

Phase 1

  • Stalagg has a war stomp ability that does around 1500 physical damage, and does not stun. In addition, he will randomly get a buff called Power Surge which increases his attack speed by 200% and lasts 8 seconds. As well, he breaks the normal rules for crushing blows. Everything that isn't dodged, parried, or blocked will be crushing, it is imperative that healers be on the ball and that tanks keep Shield Block up.
  • Feugen has an AoE mana drain ability and a War Stomp AoE that deals about 1500 physical damage to everyone in melee range.
  • Both sub-bosses initially stand near lightning rods. If a sub-boss is pulled away from these rods, they will chain-lightning the raid. Every 20.6 seconds both sub-bosses knock the current tank over to the other platform, forcing a tank transition. They are both vulnerable to taunt.

Phase 2

When both adds are down, players have a few seconds to get to the central platform before Thaddius is engaged.

  • Every 30 seconds he will give everyone in the raid either a positive or a negative charge (even distribution of charges), which appear as debuffs. Every 5 seconds charged players will deal 2000 nature damage to all opposite-charged players within 10 yards. Additionally, the debuff will grant a 10% damage bonus to all same-charged players also within 10 yards. Hence, the raid will want to cluster up in 2 or more positions.
  • Thaddius also has a chain lightning attack that he will do throughout the fight. Because of the even distribution of the charges, assuming you have up to 40 alive, you will have up to 19 stacks of the damage buff (adding 190% more damage) until Thaddius charges the raid again.
  • If he has no one in melee range, he will start throwing Ball Lightings for around 8000 Nature damage.
  • After 5 minutes in phase 2, he will enrage and kill the entire raid, similar to many other bosses.


Phase 1

Simply tank each sub-boss near where they start and DPS them down. Players with mana bars should fight Stalagg, while everyone else should fight Feugen. Mages and hunters can outrange the mana drain, so if the groups are too uneven then they can fill in for the missing spots. Note that they sub-bosses must be killed within a short time of each other, or they will resurrect each other (much like Thekal in Zul'Gurub).

Phase 2

All players head to Thaddius himself. There is roughly 20 seconds between killing both sub-bosses and getting charged. Before the raid, assign locations for positive and negatively charged people to stand; for example, negatively charged people could stand west of Thaddius, while positively charged players stand to the east. Thaddius will make a Polarity Switch roughly every 30 seconds. Players whose polarity changes have 5 seconds to run to the location for their new polarity. There is no need to avoid other players changing sides, and they should run straight to his new position, using the shortest path available (that is, running through Thaddius). It is important to stand in 2 positions because Thaddius must be killed within 5 minutes (to avoid the Enrage) and the damage bonus from stacking players on either side will allow him to be killed.

Note: If you chronically miss the jump heading for Thaddius, use a Swiftness Potion and just run forward without jumping, you will land on the platform. Rogues can use Sprint instead.


Thaddius doesn't deal very much melee damage to the main tank, so you can use only 3-4 healers for him. The rest of the healers can either heal the rest of the raid, or deal damage to Thaddius in this phase.


Thaddius hits for about 2k normal, 3.3k crushing. The damage multiplier the rest of the raid has can make holding threat for a warrior tank a little bit iffy. (Bear tank threat generation benefits from the damage multiplier, unlike warrior abilities, and is advantageous for this fight.)

In order to have a prayer of holding threat, the MT has to move with others of his charge, if he's unstacked by the debuff, he will find himself making frequent use of his Taunt button (Thaddius is tauntable).

Assumed Strategy

A wireframe and textured model of Thaddius

Blizzard's release of the Anatomy of a Monster: Thaddius revealed some clues into the strategy of fighting this abomination.

At the start of the encounter, the players don't fight Thaddius himself; they battle two wights that are in the same room on two separate platforms. These platforms are not directly connected, so to fight them the raid has to split up and attack both wights at the same time. But it gets worse... the wights have the ability to snatch a player from one platform and pull him to the other, which is a way to split up the raid and divide their forces.

One central part of the whole Frankenstein myth is the way the monster was brought to life using lightning and electricity. Voltage is created when electric charges are separated; when the charges are brought together, the stored energy is released in an electrostatic discharge - a basic electric shock. When players finally go up against Thaddius, he will "polarize" the raid group by making half the raid positive and the other half negative. When positive and negative raid members get too close to each other... Well, let's just say that you want to get as far away from players with an opposite charge as possible, which further plays into the idea of separating the raid.

Thaddius at lvl 70

  • Tactical fight like at lvl 60. Don't let your own raid members kill you - MOVE!


  • You are too late... I... must... OBEY!
Killing a player
  • Now YOU feel pain!
  • You die now!
  • Thank... you...

The following quotes (echoing screams would probably be more accurate) are heard echoing throughout Naxxramas in addition to during the fight with Thaddius, and will stop after Thaddius dies. The screams sound like those of a woman or child:

  • Pleeease!
  • Stop, please stop...
  • Help me! Save me!
  • Please, nooo!

The music video of Aphex Twin's song "Come to Daddy" has voices the same as or very similar to the echoing screams in Naxxramas described above (Particularly the "Stop, please stop..." line). Whether this is a deliberate addition by an Aphex Twin fan who works for Blizzard or the recorded sounds merely sound the same is a matter of speculation.


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Inv trinket naxxramas02.png
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External links