How to tank Halfus Wyrmbreaker

When the Slate Dragon is up, Halfus will put a healing debuff on the tank every time he attacks. If the Nether Scion is also up, he'll put a +100% attack speed buff on Halfus, and needs to be released right away, because otherwise, the healing debuff will stack much faster.

The healing debuff is called Malevolent Strikes, and reduces healing recieved by 6% each stack, stacking up to a maximum of 15 stacks (90% healing reduction).

So it is obvious that there must be tank switching, but how?

Tanks must switch Halfus every N stacks (usually about 10) of Malevolent Strikes. If the off-tank is busy tanking the drakes, it is handy to use a bubble or Hand of Protection on the main tank on the first 15 stacks; then the tank will retaunt Halfus. Divine Shield also works quite well.

Here's a report of someone who did it this way:
"So.. We picked The Storm Rider and The Nether Scion. Used Time Warp and nuked the Nether dragon first, while the dragon was about to die the tank had around 15 debuffs - one of our palas used a Hand of Protection on the tank which disspelled the buff. The tank has retaunted it back. After that we killed the second dragon, MT was about to have again 15 debuffs so he switched with the OT. MT was now on the last percentes on the dragon and OT was on Halfus. After gettin 15 debuffs second paladin used again Hand of Protection on the OT (which was not needed to be honest because the debuffs on MT were already gone and he could easly taunt it)."

Since we have some paladin healers who can give Hand of Protection, and a paladin tank who can Divine Shield himself, we should be able to use this tactic. But anyway, have a read of this next which used a druid tank and a death knight:

Pull time :
MT1 on Halfus, MT2 freeing Scion, a rogue freeing Slate.
Hunt's misdirection on the Slate to the MT2
Rogue's TotT on the Scion to the MT1.

When 2 dragons are freed
MT2 taunt Halfus, MT1 (with 3 or 4 debuff) tank the the Slate ---> MT1 Slate , MT2 Halfus + Scion

When the MT2 has more debuffs than the MT1, the MT1 taunts the Scion --> MT1 Slate + Scion, MT2 Halfus.

When the MT1 lost its debuff OR the MT2 got more than 7 or 8 debuff, the MT1 taunts Halfus, the MT2 taunts the Scion --> MT1 Halfus + Slate (by this time the Slate is nearly dead or already dead depending on the raid dps.

When Slate dies, the rest is pretty clear and your success or failure depends mainly on your healer's mana.
MT1 and MT2 exchange Halfus (and Scion if not dead) as soon as the one without halfus got no debuff and has sufficient life (more than 50%)

One important thing : We never got an MT over than 6, 7 or 8 debuffs, each time we got more --> MT died or something went wrong.