Icecrown Citadel Raid Guide for Every Boss and Wing

Icecrown Citadel is the final raid of Wrath of the Lich King. It has 12 bosses spread across five wings, ending with the Lich King on the Frozen Throne. This guide covers how to get in, how each wing is laid out, the mechanics that wipe raids on every boss, and what changes on heroic. It also covers the loot, mounts and achievements that keep players farming it years later.

What Icecrown Citadel Is

Icecrown Citadel (ICC to everyone who ever pugged it) arrived in patch 3.3, “Fall of the Lich King,” in December 2009. It was the last major raid tier of Wrath. The Ruby Sanctum arrived later in 3.3.5, but that was a single-boss side raid. ICC is where the expansion’s story pays off. The Argent Crusade and the Knights of the Ebon Blade join forces as the Ashen Verdict, push into Arthas’s fortress, and climb toward the Frozen Throne.

The raid runs in four versions: 10-player normal, 25-player normal, 10-player heroic and 25-player heroic. Each raid size has its own weekly lockout. Normal and heroic share the lockout for that size, because you toggle heroic boss by boss once it is unlocked.

ICC came back with Wrath of the Lich King Classic in 2023 as the expansion’s final content phase. A whole new generation learned to fear Defile there. On retail it is a legacy raid that max-level characters can clear solo. People run it there for transmog, the Shadowmourne questline and the Invincible mount. Those are the three versions you are likely to see today, and the mechanics below apply to all of them. In Classic you need them to survive. On retail they mostly explain why certain bosses still trip up solo players.

The raid also has a clear sense of place. The Lower Spire is all bone and cultist ritual. The Plagueworks are Putricide’s toxic laboratory. The Crimson Hall belongs to the San’layn vampires, and Frostwing Halls house Sindragosa and her captive green dragon. The Frozen Throne sits at the very top of the spire with nothing around it but wind and ice.

Icecrown Citadel Location and How to Get In

The citadel sits in the heart of the Icecrown zone in northern Northrend. You can’t miss it: it is the giant spire visible from most of the zone. The raid entrance shares a front door with the Frozen Halls, the three five-player dungeons (The Forge of Souls, Pit of Saron and Halls of Reflection) that launched alongside it.

You need to be level 80. There is no attunement for the raid itself. The five-player Frozen Halls have their own quest chain, but you can skip it and walk straight into the raid.

In original Wrath and in Wrath Classic you need Cold Weather Flying to fly in Northrend, so most players fly directly to the spire. Without it, the ground route through Icecrown is long and full of elites. On retail any modern flying mount gets you there in seconds. Many players also use the Dalaran portal network and fly north.

How to Leave Icecrown Citadel

New raiders ask this more often than you would think, usually after a wipe on Lady Deathwhisper. You have a few options:

• Run out the front. The Light’s Hammer teleporter near the entrance takes you back to the start, and the zone-out portal is a short walk from there.
• Hearthstone. This is the fastest exit if your hearth is up and set somewhere useful.
• Mage portal or Dalaran teleport. Any mage in the group can port everyone out.
• Leave the group. On retail, leaving the instance group starts a short timer and then removes you from the instance.

You can only use the teleporters for wing checkpoints you have already unlocked, which brings us to the layout.

Icecrown Citadel Boss List by Wing

The raid is split into the Lower Spire, then three wings branching off the Upper Spire, then the Frozen Throne. You must clear the Lower Spire first. After that, the Plagueworks, the Crimson Hall and Frostwing Halls can be done in any order. All three final wing bosses must be dead before the Frozen Throne teleporter opens.

Teleporters and How They Unlock

ICC’s teleporter network is one of its best quality-of-life features. You can skip cleared sections on later attempts, and after a wipe you are back at the boss quickly.

Difference Between Normal and Heroic Mode in ICC

Heroic does more than inflate health bars. Almost every boss gains at least one new mechanic, and some of them reshape the fight entirely. Putricide stops pausing during his transitions, Lana’thel’s bite chain gets harsher, and the Lich King adds Shadow Traps and a raid-wide trip into Frostmourne.

Loot scales with difficulty and size. Here is how item levels line up:

10 heroic and 25 normal drop the same item level. In Wrath Classic that shaped how guilds planned their weeks. A strong 10-player group running heroic kept pace with a casual 25-player group on normal.

The zone also carries a stacking raid buff (Strength of Wrynn for the Alliance, Hellscream’s Warsong for the Horde). It raises health, healing and damage, and it grew in steps over the raid’s life. It’s why late-patch pugs could clear bosses that walled guilds in the first weeks. Some progression guilds deliberately turned it off for bragging rights.

Lower Spire Strategy

The Lower Spire covers four bosses. The first two are a fair test of whether your group can follow instructions, and the last two test your damage.

Lord Marrowgar

Marrowgar is a damage check with a few movement rules. Two tanks stack on him to share Saber Lash, a frontal hit split between nearby targets. If only one tank is in range, that tank eats the whole thing and dies.

Three mechanics matter:

• Bone Spike Graveyard impales random players on spikes. DPS must switch and break them fast. Healers keep the impaled player alive, because they take ongoing damage and can’t move.
• Coldflame sends a line of frost fire along the ground toward a player. Sidestep it rather than running down its path.
• Bone Storm turns Marrowgar into a whirlwind that charges between players. The tank threat table clears during it. Ranged spread out, melee back off, and everyone runs from his path.

On heroic, Bone Spike Graveyard keeps firing during Bone Storm. That’s where weak spike-switching gets punished. The achievement for this fight, Boned, requires that nobody stays impaled for more than eight seconds. It makes a good benchmark for your DPS reaction time even if you aren’t chasing it.

Lady Deathwhisper

Deathwhisper is the first real coordination fight in Icecrown Citadel, and in Wrath Classic she ended more pug runs than any other Lower Spire boss.

Phase one starts with her shielded by Mana Barrier. Damage to her drains mana instead of health. While you burn through it, cultists pour in from side doors on alternating sides of the room:

• Cult Adherents are casters. Interrupt them and kill them. She will empower some into a stronger form or reanimate them.
• Cult Fanatics are melee. Keep them off your healers, and watch for them transforming into Deformed Fanatics, which need slowing and kiting.

She drops Death and Decay under groups, which you move out of immediately. Assign your off-tanks and some DPS to the adds, and keep the rest on her mana.

Phase two begins when her mana is gone. Now she is tankable. Touch of Insignificance reduces her current tank’s threat, so tanks swap at a few stacks. Frostbolt must be interrupted. Summon Spirit creates vengeful shades that drift toward a player and explode, so the targeted player kites them away from the raid.

On 25-player and on heroic, Dominate Mind turns raid members into hostile mind-controlled players. Crowd control them rather than killing your own healer. Adds keep spawning in phase two on heroic, so your add team can’t relax.

Icecrown Gunship Battle

This is the encounter people either love or forget exists. Alliance players fight from the Skybreaker against Orgrim’s Hammer, and Horde players do the reverse. The goal is to destroy the enemy ship. Cannons do most of the damage, and your boarding team keeps the enemy from crippling your side.

How it plays out:

1. Two players man your ship’s cannons. Cannons build heat as they fire, and overheating stops them, so use your stronger shot without maxing the bar.
2. A boarding team uses rocket packs from the goblin on your deck to fly across to the enemy ship.
3. The boarding team kills the enemy mage, who freezes your cannons with Below Zero. Then they deal with the riflemen and mortar crews firing at your deck.
4. Tanks on your own ship pick up enemy boarders when they portal over, along with the enemy captain’s attacks if he comes aboard.

The enemy captain (Muradin Bronzebeard or High Overlord Saurfang, depending on your faction) gains strength as the fight drags on. Don’t fight him on his deck longer than you have to. Your boarders should return when the mage is down and the cannons are firing again.

Deathbringer Saurfang

Saurfang is a tight DPS race with one rule your healers must understand. He builds Blood Power as he deals damage. When the bar fills, he casts Mark of the Fallen Champion on a player. That player takes extra damage every time he hits anyone, and if a marked player dies, Saurfang heals.

So every mark makes the fight harder, and the whole strategy revolves around giving him as little Blood Power as possible:

• Blood Beasts spawn in waves and give him Blood Power when they hit players. Slow, stun and kill them at range before they reach anyone. On heroic they gain Scent of Blood, which makes this harder.
• Rune of Blood goes on the tank and feeds him. Swap tanks when it lands.
• Boiling Blood and Blood Nova add raid damage. Spread out to keep Blood Nova splash low.

He frenzies at 30%, which is where you pop Heroism or Bloodlust. The achievement I’ve Gone and Made a Mess asks you to kill him before he casts more than three marks. Regardless of the achievement, that target is a solid health check for your raid’s DPS.

The Plagueworks Strategy

Putricide’s wing is the mechanical high point of the raid. Each of the two minibosses guarding the doors foreshadows the boss behind it: Stinky before Festergut and Precious before Rotface. Putricide then combines elements of both into one fight.

Festergut

Festergut is the cleanest tank-swap fight in Icecrown Citadel. Every melee hit applies Gastric Bloat to the current tank. If the stacks climb too high, the tank explodes, so tanks trade around the high single digits.

The raid’s challenge is Inhale Blight. The room fills with gas, and Festergut inhales it three times, getting stronger each time. Then he exhales Pungent Blight, which hits the whole raid hard. Your defense is Gas Spores. Each spore lands on a player and explodes after a few seconds, granting nearby players Inoculated. That debuff reduces blight damage and stacks.

• Gas spore targets run to pre-assigned spots, and the raid stacks on them.
• Ranged spread when Vile Gas goes out, so the debuff doesn’t splash between them.
• Make sure the whole raid is inoculated before Pungent Blight.

On heroic, Professor Putricide joins from the balcony and throws Malleable Goo, slowing anyone hit. The achievement Flu Shot Shortage has you defeat him with nobody gaining more than two stacks of Inoculated. That means the raid has to plan who stands where through each spore set.

Rotface

Rotface is the fight where one off-tank decides the outcome. Mutated Infection goes out to random players and spawns a Little Ooze from them when it expires or is dispelled. The off-tank picks up Little Oozes and kites them around the room.

When two Little Oozes meet, they merge into a Big Ooze. Big Oozes absorb other oozes, and once one has merged enough times it explodes with Unstable Ooze Explosion, raining damage across the room. The off-tank’s job is to merge oozes in a controlled way, kiting the Big Ooze along the outer edge while ranged blow up and destroy as many spare oozes as they can.

The main tank holds Rotface in the center, facing away from the raid because of Slime Spray. Ooze Flood periodically drowns sections of the floor, so check the pipes.

On heroic, Putricide joins in again, this time with Vile Gas. The achievement Dances with Oozes asks you to kill Rotface with no Big Ooze exploding. It’s the real test of your off-tank’s kiting.

Professor Putricide

Putricide is three fights in one, and the boss most guilds remember from Wrath progression. He changes phase at 80% and 35%.

Phase one brings his Unstable Experiment, which spawns oozes from vats on either side of the room:

• Volatile Ooze (green) links to one player and moves toward them. The raid stacks on that player so the ooze’s explosion is split among everyone.
• Gas Cloud (orange) puts Gaseous Bloat on its target, who kites the cloud while the raid kills it. Stacks drop as it hits the target.

You also choose one player to drink from the vat at his table and become the Mutated Abomination. The abomination eats the slime puddles that spread across the floor. It also slows the oozes with Regurgitated Ooze, which buys time for the stack and the kite. Pick someone calm with good situational awareness, not your top DPS.

Phase two adds Malleable Goo and Choking Gas Bomb. Dodge both.

Phase three removes the abomination. The tank now accumulates Mutated Plague, which pulses stacking damage to the raid. Tanks swap to keep the stacks reset, and healers ramp up throughout this phase. It is a race, and you’ll want Heroism here if you didn’t use it earlier.

On normal, Putricide uses Tear Gas during transitions, stunning the raid while he drinks a potion. On heroic he keeps fighting through transitions and adds Unbound Plague, which bounces between players and needs constant attention. Heroic Putricide is one of the hardest fights in Wrath, and it remains a benchmark for raid leaders.

The Crimson Hall Strategy

The San’layn wing is shorter but punishing. Both bosses demand constant attention to buffs and debuffs.

Blood Prince Council

You fight three princes, Valanar, Keleseth and Taldaram, who share one health pool. Only one prince is empowered at a time by Invocation of Blood, and damage dealt to the others is negligible. Your DPS needs to swap targets the moment the empowerment moves.

Each prince brings his own problem:

• Prince Valanar spawns Kinetic Bombs that float slowly toward the ground. Ranged hit them to push them back up. He also casts Shock Vortex and, when empowered, Empowered Shock Vortex, which requires the raid to spread.
• Prince Keleseth casts Shadow Lance and summons Dark Nuclei. His tank collects the nuclei to absorb his damage. Many 10-player groups use a warlock tank or another ranged tank for this prince.
• Prince Taldaram throws Glittering Sparks and Conjure Flame. Its empowered version is a fireball that chases a player and grows as it travels. The targeted player kites it as far as possible before it hits them.

On heroic, Shadow Prison deals stacking damage whenever you move. That makes Kinetic Bombs and flame kites far more costly. Assign movements in advance so nobody wastes steps.

Blood-Queen Lana’thel

Lana’thel is the boss everyone remembers as a social experiment: who bites whom, and did they bite in time.

The fight opens with Vampiric Bite on a random DPS player. That player gains Essence of the Blood Queen, which dramatically raises their damage. After a while they get Frenzied Bloodthirst and must bite another raid member within a short window. If they don’t, they suffer Uncontrollable Frenzy and become hostile. The bite chain doubles with every round, so your raid leader needs a clear bite order. DPS first, then healers, with tanks excluded.

Other mechanics:

• Pact of the Darkfallen links several players. They take damage until they move together, which clears the debuff.
• Swarming Shadows leaves a trail of shadow behind the targeted player. Run it to the edge of the room and drop it there.
• Twilight Bloodbolt splashes nearby players. Spread out.
• Blood Mirror copies damage taken by the tank onto a second player, usually the off-tank.

She has an air phase with Bloodbolt Whirl, where everyone spreads and healers work hard. Her enrage timer is famously short at 5 minutes 20 seconds, which makes this one of the strictest DPS checks in ICC. The Once Bitten, Twice Shy achievement flips between sizes. One size wants a vampire to land the kill and the other wants a non-vampire. Check which applies before you go for it.

Frostwing Halls Strategy

Frostwing Halls opens with a trash gauntlet led by Sister Svalna, where you fight alongside Crok Scourgebane and his captains. Clear it with care, because those trash packs hit harder than most bosses in the Lower Spire.

Valithria Dreamwalker

Valithria flips the usual raid formula: you heal the boss instead of killing it. She starts at 50% health, and you win by healing her to 100%. You lose if she dies.

Your DPS and tanks have a busy fight of their own. Portals around the room spawn waves of undead:

• Risen Archmages cast Frostbolt Volley and create Mana Voids that drain healers’ mana. Move out of the voids.
• Blazing Skeletons cast Lay Waste, a heavy raid-wide fire attack. Kill them quickly.
• Suppressers reduce healing on Valithria. They are a top priority.
• Blistering Zombies explode with acid on death. Kill them away from the raid.
• Gluttonous Abominations cleave in front and release Rot Worms when they die.

Valithria periodically opens Dream Portals. Healers who enter can collect clouds in the dream that grant Emerald Vigor, which significantly increases their healing on her. Heroic adds Nightmare Portals and constant damage on Valithria. Your healers need more coordination with the portal rotation, and they get less time to recover mana. The Portal Jockey achievement is as simple as it sounds: go through a dream portal.

When she reaches full health, she transforms and casts Dreamwalker’s Rage, ending the fight and unlocking the Sindragosa’s Lair teleporter.

Sindragosa

You need to kill Spinestalker and Rimefang, her two frost wyrm escorts, before Sindragosa lands. She is the encounter most raids underestimate, especially on 25-player.

Phase one is the ground phase:

• Frost Breath goes on the tank, who swaps at stacks.
• Cleave and Tail Smash punish anyone standing in front or behind. Everyone stands to her sides.
• Permeating Chill stacks on melee. Melee DPS step out briefly to reset when stacks climb.
• Unchained Magic marks casters and healers. Each spell they cast adds a stack of Instability, which explodes when the debuff expires. Cast in short bursts and then wait.
• Icy Grip pulls everyone to her, followed by Blistering Cold. Run out fast or die.

Air phases come on a timer. Frost Beacon marks players who become Ice Tombs. The raid hides behind those tombs to break line of sight from Frost Bomb, then DPS break them open.

Phase three begins at 35%. Sindragosa now applies Mystic Buffet, a stacking debuff that raises magic damage taken. To drop your stacks, you break line of sight behind an Ice Tomb. Frost Beacon now comes on one or two players at a time, and the raid plays a constant dance around those tombs. The All You Can Eat achievement asks you to defeat her without anyone exceeding five stacks of Mystic Buffet. That gives your raid a solid way to measure how well everyone handles phase three.

The Lich King Strategy

Arthas is the end of Wrath’s story, and one of the most iconic encounters in WoW. The fight has three phases, two transition phases at 70% and 40%, and a scripted finale at 10%.

Phase One

The Lich King stands at the center of the Frozen Throne platform, attended by two adds that arrive in waves:

• Drudge Ghouls pile in. Off-tanks pick them up, and AoE kills them.
• Shambling Horrors cast Shockwave, a frontal cone. They also Enrage, which hunters and rogues can soothe or remove.

His main mechanic is Necrotic Plague. When dispelled or when it expires, it jumps to a nearby target and gains a stack. Your dispellers and plague targets move it onto Shambling Horrors so they stack up damage on adds instead of players. Infest deals damage to the whole raid that continues until each player is healed above 90%. Healers spike-heal everyone quickly.

First Transition (70%)

Arthas moves to the center and casts Remorseless Winter, an aura that deals heavy frost damage to anyone near him. Spawning Raging Spirits need tanking and killing. Ice Spheres float toward players and hit them with Ice Pulse, so ranged kill them. Pain and Suffering goes out in a frontal cone. At the end, Quake destroys the outer edge of the platform. Stay out of the last ring.

Phase Two

Now the Lich King adds two of the most famous mechanics in WoW raiding:

• Defile drops a pool of shadow under a player that grows each time it deals damage. The targeted player moves out instantly. A good raid makes Defile a non-event; a bad one fills the platform with shadow in seconds.
• Val’kyr Shadowguards grab players and carry them toward the edge of the platform. You need to stun, slow and kill them before they drop their victims off the side. There’s one Val’kyr on 10-player and three on 25-player.

Soul Reaper goes on the tank, so swap or use a defensive cooldown. Infest continues throughout, and healers must manage it alongside everything else.

Second Transition (40%)

The second transition repeats the first: Remorseless Winter, Raging Spirits, Ice Spheres. Practice gets it done.

Phase Three

Phase three is the hardest of the fight:

• Vile Spirits spawn and drift toward random players. They explode with Spirit Bomb on contact. Ranged and melee kill them on the move.
• Harvest Soul pulls a player into Frostmourne. Inside, they fight the Spirit Warden with the help of King Terenas Menethil’s spirit. They must keep Terenas alive and defeat the warden to return.
• Defile continues and grows larger.
• Soul Reaper continues on the tank.

At 10%, Arthas casts Fury of Frostmourne and kills the raid. This is scripted. Tirion Fordring breaks free and shatters Frostmourne, and Terenas resurrects your raid so you can finish the fight. Nobody in a guild forgets their first kill on him.

On heroic, the Lich King adds Shadow Trap, a pool that throws players off the platform. Val’kyr and Vile Spirits behave differently, and Harvest Soul becomes Harvest Souls, pulling the entire raid into Frostmourne at once. Heroic Lich King on 25-player was the last major raid kill of Wrath, and in its era it ranked among the hardest fights Blizzard had ever shipped.

Icecrown Citadel Drops and Rewards

Tier 10 Sets

Tier 10 comes from two sources in ICC. You can buy the base set with Emblems of Frost, which drop from every ICC boss and the daily heroic. Tokens then upgrade it: Marks of Sanctification drop from 25-player normal and 10-player heroic bosses, and Heroic Marks of Sanctification from 25-player heroic.

Most classes have separate armor sets for each role, such as a healing set and a DPS set for paladins and shamans. Make sure your tokens and emblems go toward the correct pieces. Tier 10 is one of the most popular transmog sets in WoW. The Lightsworn and Scourgelord’s sets in particular still sell well on retail. If you also play FFXIV, our “ff14 glamour” guide covers how that game’s appearance system compares.

The Ashen Verdict Rings

The Ashen Verdict is ICC’s reputation faction, and you build standing by killing trash and bosses inside. When you reach Friendly, the quartermaster at Light’s Hammer sells you a ring in one of several role lines: caster, healer, tank, melee or strength DPS. You upgrade it at Honored, Revered and Exalted. The Exalted version is a best-in-slot ring for most of Wrath’s final tier, so pick your role line carefully.

Shadowmourne

Shadowmourne is the legendary two-handed axe of Icecrown Citadel. Warriors, paladins and death knights can wield it. Highlord Darion Mograine gives the questline inside ICC, and it requires 25-player clears across many weeks. You collect Shadowfrost Shards and other materials from specific bosses, and you defeat several bosses with special conditions. In Wrath Classic, a guild usually funneled shards to one player at a time. On retail you can farm the entire questline solo, so it’s a popular legacy project.

Weekly Raid Quest

The weekly raid quest from Light’s Hammer rotates between objectives tied to specific bosses, such as Lady Deathwhisper, the Gunship Battle, Putricide, Lana’thel and Valithria. It rewards extra Emblems of Frost. Pick it up each week before your first pull.

ICC Mounts and Achievements

ICC has three mount rewards:

Invincible is Arthas’s skeletal steed and the raid’s prestige mount. Its drop rate is very low. Retail players have farmed it weekly for over a decade without seeing it, which makes it one of the most famous long farms in WoW.

The Glory meta-achievements require you to complete a dozen boss-specific achievements. You’ve seen most of them above:

• Boned (Marrowgar)
• Full House (Deathwhisper)
• I’m on a Boat (Gunship Battle)
• I’ve Gone and Made a Mess (Saurfang)
• Flu Shot Shortage (Festergut)
• Dances with Oozes (Rotface)
• Nausea, Heartburn, Indigestion… (Putricide)
• The Orb Whisperer (Blood Prince Council)
• Once Bitten, Twice Shy (Lana’thel)
• Portal Jockey (Valithria)
• All You Can Eat (Sindragosa)
• Been Waiting a Long Time for This (Lich King)

The Lich King achievement asks you to let Necrotic Plague reach 30 stacks before the kill. It’s one of the trickiest of the set. On retail, solo players can complete most of the Glory achievements, although some require mechanics that are easier with a friend.

Building a Raid for ICC

For Wrath Classic or an organized retail achievement run, raid composition matters on several bosses:

• Tanks: Bring three on 25-player. Valithria, Rotface and Deathwhisper all benefit from an extra tank, and Blood Prince Council needs a dedicated Keleseth tank.
• Healers: Bring two or three on 10-player and five to seven on 25-player. Valithria and heroic Lich King demand the most.
• DPS: Lana’thel’s enrage and Saurfang’s Blood Power make raw DPS critical. Ranged DPS are especially valuable for Valithria, Kinetic Bombs and Val’kyr.

Bring at least one hunter or rogue for Shambling Horror enrages. Also make sure you have enough dispellers for Necrotic Plague and stuns or slows for the Val’kyr.

Retail Solo Farming

On retail, a max-level character can clear ICC alone, but a few fights still need care:

• Gunship Battle: Grab the rocket pack, board the enemy ship and kill the captain, or keep your cannons firing.
• Lana’thel: Her bite mechanics are moot solo, but she still enrages. You’ll outgear the timer easily.
• Valithria: Since you can’t heal her the way a raid would, you kill the adds and let the encounter progress. A modern character should finish it in a few minutes.
• The Lich King: The scripted 10% finale still plays out. Don’t panic when Fury of Frostmourne “kills” you.

Most players farm 25-player heroic each week for Invincible, the Shadowmourne quest and Tier 10 transmog.

FAQ

How many bosses are in Icecrown Citadel?

Twelve bosses across five wings: the Lower Spire, the Plagueworks, the Crimson Hall, Frostwing Halls and the Frozen Throne.

What level do you need for Icecrown Citadel?

You need to be level 80 in Wrath of the Lich King and Wrath Classic. On retail, any max-level character can solo it.

Can you do the ICC wings in any order?

The Lower Spire must be cleared first. After that, the Plagueworks, Crimson Hall and Frostwing Halls can be done in any order. All three final wing bosses must be dead to open the Frozen Throne teleporter.

Does Invincible drop on 10-player heroic?

No. Invincible’s Reins only drops from the Lich King on 25-player heroic.

How do you unlock heroic Icecrown Citadel?

In Wrath Classic, you toggle heroic for each boss individually through the difficulty setting. There is no requirement to defeat the Lich King on normal first.

Can you solo ICC on retail?

Yes. Any max-level character can clear all 12 bosses solo on retail. Most players farm 25-player heroic each week for transmog, Shadowmourne and Invincible.