Health:

• Heroic:  32M
• Normal:  8.4M
• 8 minute enrage

Abilities:

• Biting Cold:  Deals increasing periodic damage to stationary enemies. Movement diminishes this effect. This aura uses the same mechanics as Intense Cold during the fight against Keristrasza in the Nexus, it stacks up and damage increases over time. Moving or staying near a Toasty Fire will lower the amount of stack.
• Flash Freeze:  Encases the target in a block of ice. This spell will freeze the entire raid in blocks of ice, you can avoid this spell by standing on Sspawned by Icicle. 9 sec cast, 30 sec cooldown
• Freeze:  Inflicts 5550 to 6450 Frost damage to nearby enemies, immobilizing them for up to 10 sec. 10 yd radius. The root effect of this spell is dispellable.
• Icicle:  Icicles will randomly drop on the ground during the fight. Move before they hit the ground, they will deal 12,000 damage on impact. After an Icicle crashed on the ground it will create a Snowdrift, standing on it will protect you from the effects of Flash Freeze.
• Frozen Blows- Reduces Hodir's physical damage by 70%, but grants each of his attacks 31,062 (Heroic: 40,000) additional Frost damage, for 20 seconds. Enemies take 4,000 additional Frost damage every 2 seconds for the duration of the spell.

NPCs:

There will be 8 friendly (4 in normal) NPCs that we can release to help with the fight.   They start off in ice blocks to attack to release.   Not absolutely neccessarly, but they do dps themselves and buffs, and help dispels too.    Also don't release them before Hodir is pulled or they despawn for the fight.

Moonkins:

• Starlight:  Envelops a location in starlight for 1 min, increasing the attack and casting speed of friendly units within it

Shamans:

• Storm Power:  Charges a nearby friendly target with lightning, increasing critical strike damage by 135% for 30 sec.

Priests:

• Dispel:  Dispell Priests will randomly dispell Freeze on the members of the raid.

Mages:

• Toasty Fire:  Warms nearby friendly creatures, preventing the effects of Freeze and Biting Cold, and increasing Spirit by 4. In addition, your Spells and Ranged attacks have a chance to singe enemies. Toasty fire can be extinguished by falling ice or Flash Freeze.
• Singed:  Singes the enemy, inflicting 3000 Fire damage and increasing damage taken from magical spells and effects by 2% for 25 sec. Stacks up to 30 times.

Hard Mode:

Kill him in 3 mins or less.

The Fight:

This is a fairly simple fight actually.   First note, only need 1 tank, and a Nuitbear in polar Frost Resist gear with 50K hp would be perfect tank for this.   Other tanks are doable too, don't need Frost Resist per se, with enough HP at least.   It's only that 40K frost damage blow which can probably be reduced with CDs like Sarth3D breath coordination type of thing.

Most of the raid damage is avoidable.  The better we're at avoiding, the less healers we need for the fight.

Jump/run all the time to avoid the dot from stacking, like Nexus.  Avoid the Icicles that fall from the sky, watch for the snowflakes, think Gruul rocks.   Turn on your projected textures, these icicles are the blue circles on the ground you have to stay away from.

For Flash Freeze, can completely avoid it by being where Icicles already landed, they form Snowdrifts.  During it's cast, 3 large icicles (2 in Normal) will start to drop.   Get near one of these, just outside of it until the snowdrift forms, then strafe on it.   If one should fail to avoid this, they will be encased in an Ice Block.   That's when we have to hit the Ice Block to release him, should they be hit with Flash Freeze again while in a block, they die.

As for the NPCs, if we choose to work with them, we gotta release em from the Ice Blocks.   They give us buffs, they help dispels, they even dps the boss.   They are also vulnerable to Flash Freeze and not as smart as some of us.  So we'd likely have to release them each time if we want to keep them around.

That's basically it, 8 minute enrage.    Use the lights, use the fires, dps boss, avoid icicles, never stop moving, get on snowdrifts, profit.  Loot wise, he has 2 chests.   He destroys one at hard mode, one at enrage.     So Hard Mode is just killing him very fast for more loots.

Achievements:

Cheese the Freeze:  Defeat Hodir without any raid member being hit by Flash Freeze on Normal/Heroic Difficulty

Just a raid wide check to avoid damage.

I Have the Coolest Friends: Defeat Hodir without any friendly NPC dying on Normal/Heroic Difficulty.

This simply means we hit every single damn ice block to break everyone out after each Flash Freeze.   They won't die to anything else except the insta kill flash freeze while ice blocked.   Remember 8 in Heroic, 4 in Normal.

Getting Cold in Here:  Defeat Hodir without any raid member having more than 2 stacks of Biting Cold on Normal/Heroic Difficulty.

Another raid check to keep moving.   And quick dispels when people get trapped by frost nova.

Staying Buffed All Winter:  Possess the effects of Toasty Fire, Storm Power and Starlight at the same time on Normal/Heroic Difficulty.

This might take a bit of luck.   Got mine's purely by accident along with a few others.   You'd need a Starlight by a fire, and have the Shaman buff you.   Though I dunno how he chooses his targets to buff.

I Could Say this Cache was Rare:  Defeat Hodir before he shatters his rare cache on Normal/Heroic Difficulty

Hard Mode.   It's simply a defeat him within 3 mins.   On 10 man, we did this 2 healers, pretty much blind zerg of the boss.   Release the ice blocks of course, and take advantage of buffs whenever you can.  DPS!

Trash Info:

Champion of Hodir:  Single pulls, simply a big guy, has a targetted aoe breath where it freezes anyone it hits in an ice block.    Like that mage deep freeze kinda ice block though.    Think of it like those SSC bog lord that pick a member to spit poison at, and hits everyone inbetween.   Except it's ice, and it's too late if you're already hit.   Just spread out and circle around him, to mitigate the number of people hit each time.

Snowdrifts:  There'll be these steaming piles of snow.   When you approach em, Worms pop out.   Lots of them.  And one by one.   So yea, aggro can be touchy since they don't all appear at once to tank and build threat.

Elemental Packs:  There will be one big Revanant and 4 smaller Ice Rock Elementals.  The big guy puts a shield on everyone that reduces AoE damage by 90%.   What?  Is Blizz trying to say we can't aoe these?    Anyways, obviously, kill the big guy, then ezmode trash.

Videos:

10 man Hard Mode

25 Man Hard Mode

Sources:

• http://www.mmo-champion.com/index.php?page=848
• http://www.wowwiki.com/Hodir_(tactics)
• http://www.stratfu.com/strats/Hodir