If you read the news on World of Warcraft official site today, I am sure that you can see the testing on Hodir and Thorim. On the Hodir testing, we can know the details on Enrage, Biting Cold, Abilities and so on. How about Thorim testing?
Thorim
Trash HP: 2.3 to 2.5 million (Heroic)
During the trash event, the following abilities are used by Thorim.
Don't bother attacking Thorim during this phase; he's protected by Shealth of Lightning which reduces his damage taken by 99%.
Stormhammer - Throws a stormhammer, dealing 2451 to 2551 damage to an enemy, knocking down and stunning the target for 2 sec, and causing a deafening thunderclap to all enemies nearby the target.
Deafening Thunder - Inflicts 4625 to 5375 Nature damage to enemies standing in close proximity to a Stormhammer strike, preventing spellcasting for 2 sec.
Thorim throws this at targets during the trash event phase.
Berserk - Damage done increased by 500%. Attack and cast speed increased by 200%. Health increased by 300%.
Thorim casts this on the adds during the trash event if you take longer than 5 minutes to get to him.
Jormungar Behemoth Phase
Abilities
Acid Breath - Spews acidic bile at a target and nearby enemies, inflicting 12000 Nature damage and 1500 additional damage every 2 sec. for 18 sec. (10 player: 6000 Nature damage)
Sweep - Sweeps at the legs of an enemy, dealing 6000 damage and causing knockdown for 3 sec. (10 player: 3500 damage)
Thunder Orb
Charge Orb - Charges a nearby orb with electricity. Firing static bolts every 1 sec. for 15 seconds.
Lightning Shock - Inflicts 2831 to 3169 Nature damage on a nearby enemy.
Captured Mercenary Captain
Devastate - Sunder the target's armor causing the Sunder Armor effect. In addition, causes 50% of weapon damage plus 90 for each application of Sunder Armor on the target. The Sunder Armor effect can stack up to 5 times.
Heroic Strike - A strong attack that deals 3938 to 5062 additional Physical damage. (Plus weapon damage)
