Abilities:

• Meteor Smash - Deals 200,000 Fire Damage split between all targets within 65 yards in front, increases fire damage taken by 100% for 20 seconds.
• Comsuming Darkness - Inflicts 3000 shadow damage, and additional 3K shadow damage every 0.5 sec for 15 seconds, dispellable
• Fel Firestorm - Launches fireballs in the air which fall down and leaves fire patches on the ground, each doing 8.5K fire damage to all that stand in them, 3 second cast, 15 second duration.

Notes:

• Similar to Brutallus
• Split raid in 2 on either side to soak the Meteor Slash
• Tank taunts after each since you don't want to be twice in a row with that debuff
• Dispel Consuming Darkness, if you don't want to heal 90K of damage within 15 seconds
• At 66% and 33%, he pauses his main attacks and Fel Firestorm begins, so run from the fire
• Scatter to survive, dps when you can, the fire will disppear and Argaloth resumes normally so group back up in your 2 groups
• 5 minute Berserk