Molten Core
Lucifron - Magmadar - Gehennas - Garr - Geddon - Shazzrah - Golemagg - Sulfuron - Majordomo - Ragnaros
Sulfuron Harbringer
Sulfuron can be a tricky fight sometimes because of his 4 guards.
Sulfuron fight Abilities
Sulfuron's guards will heal eachother if they are close enough for about 15-20%
Sulfuron's guards will cast a SW: Pain spell likes the priests on a random person near them. This does an immense amount of damage and needs to be dispelled immediately.
Sulfuron's guards will cast immolate on a random person which does around 400 damage every 3 seconds. Dispel it.
Strategy
(Click to Enlarge)
You will need 4 designated off-tanks and 1 main-tank. Also you will need a couple of priests who will only focus on removing the SW: Pain and immolate.
When you pull you will want the 4 guards and sulfuron to be separated from eachother quite a bit or else they will heal eachother during the fight.
Have hunters pull the adds to the off-tanks and have the MT tank sulfuron right where he starts at. Pull them off to different corners of the room and one by one DPS down his guards before focus firing on Sulfuron.
Once the adds are down sulfuron is a breeze and should be easily handled after the guards are dead.