Sapphiron

Sapphiron is a boss found in the Curse of Naxxramas adventure. He is the first boss within the adventure's fifth wing, the Frostwyrm Lair, and the penultimate boss of the adventure.

Special cards
Frozen Champion is put on the battlefield for the player when the match begins, except on Heroic difficulty.

Decks
The below classes are listed purely for reference, and have no effect on the boss' use of the cards during the battle.

Prohibited cards
If summoned during the Heroic mode encounter, Kel'Thuzad will destroy Alexstrasza, refund no mana, and taunt you for your cheap tactics. This applies whether her Battlecry is applied to Sapphiron or the player.

Strategy
Including cards that freeze friendly minions can make this encounter easier. Cards include Frozen Crusher (8/8 and it freezes itself after attacking, thus making itself invulnerable to the Hero Power). Hyldnir Frostrider applies a board-wide protection on our side, while Cryostasis will freeze the target minion and give it +3/+3.

Heroic
For Heroic Sapphiron a mage deck can be used. For early/mid game try to keep the board clear and avoid damage until the boss can't have the card advantage needed to apply pressure. For this purpose use cards like Bluegill Warrior, Frostbolt, Mirror Entity, Ice Barrier, Vaporize (against Spectral Knight) and Frost Nova. Also make smart use of Fireball (e.g. on Necroknight when the timing is right), and field nukes like Blizzard and Flamestrike. During late game you can strike back with Pyroblast and any spare damaging spells. For more damage try the legendary cards Feugen and Stalagg. At 10 mana summon both of them to get 2 Thaddius. Keep a Wailing Soul in hand to counter Sapphiron's Blizzard and do 22 damage next turn. If needed, Duplicate from some previous turn can generate more Feugen or Stalagg copies.

Other suggested cards: Arcane Intellect, Nerubian Egg, Mad Scientist, Wolfrider.

Druid
Using a Milling Druid deck works great against Sapphiron.

In the early turns, Sapphiron's most common opener consists on coining for a Faerie Dragon and playing an additional one next turn, which can be counteracted by playing Explosive Sheep. Use removal spells to clear the board (such as Swipe, Force of Nature, etc) and keep Naturalize for Necroknight or the Bite + Savage Roar combo to deal with Spectral Knight. As a last resort, play Poison Seeds + either Explosive Sheep or Starfall to clear Sapphiron's side of the board.

You will have to maintain relatively high health during the duel, so Healing Touch and Antique Healbot are nice for that purpose, as well as Tree of Life (which will also heal Sapphiron, but that won't matter if you play it before fatigue starts consuming him). Meanwhile, force Sapphiron to draw cards by playing Naturalize and Coldlight Oracle.

Using this strategy, Sapphiron will run out of minions and, eventually, will start taking fatigue damage before you do the same. Employ your remaining spells to further weaken Sapphiron and victory will be yours.

Decklists

 * Hearthpwn.com - The Frostwyrm Lair Heroic Boss Deck Guides
 * Hearthhead.com - Decks to Defeat Heroic Sapphiron

Dialogue
Before match
 * Kel'Thuzad
 * ''My massive frost wyrm awaits. Dress warm.

Introduction
 * Sapphiron
 * ''*ROOOARRR*

Emote Response
 * Sapphiron
 * ''*rrrr Rrahhh!*
 * ''*grraaaaah*
 * ''*rooooaaar*

Hero Power
 * Sapphiron
 * ''*roooarrr*

Turn 1
 * Kel'Thuzad
 * ''Look at that little gnome. He used to be an interloper LIKE YOURSELF.

Sapphiron's turn 5
 * Kel'Thuzad
 * ''Stop hiding behind that block of ice!

Pure Cold
 * Sapphiron
 * ''*rrrrrAAAHH*
 * Kel'Thuzad
 * ''Sapphiron, execute plan: "FREEZE THE BLOOD IN YOUR VEINS"

Play Alexstrasza in Heroic mode
 * Kel'Thuzad
 * ''This is heroic Naxxramas! I won't stand for such cheap tactics here!

Death
 * Sapphiron
 * ''*roooarrr...*
 * Kel'Thuzad
 * ''My dragon! I DO NOT LIKE YOU.

Curse of Naxxramas
''Once one of Malygos’ blue dragonflight, was slain by  and raised from the dead to guard Kel'Thuzad for all of eternity. Like many of the, Sapphiron had immense magical power, which was only magnified by the fact that the personally resurrected him to serve the. The chill of frost is at his command, and he uses his magic to defend Kel'Thuzad at all costs. ''

While described in the above official profile as being resurrected by the Lich King, Sapphiron was in fact resurrected by, the human death knight (and former paladin) who would later go on to merge with the Lich King.
 * Trivia

In World of Warcraft

 * "Once a noble within the mountains of,  was slain by  during his campaign through the frozen north. Resurrected to serve him, Sapphiron guards Kel'Thuzad's lair eternally, awaiting those who would dare trespass upon his master."
 * ''—Commander Eligor Dawnbringer

History
Sapphiron was intended to be a collectible reward from the Curse of Naxxramas adventure. He was originally designed as a 9 Mana 8/8 minion with the ability "Battlecry: Deal 3 damage to a minion and the minions next to it, then Freeze them."

Patch changes

 * Added.