Thane Korth'azz

Thane Korth'azz is one of the Four Horsemen of Naxxramas. He holds the power of flame, being even able to call forth fiery meteors from the skies.

Korth'azz is a fallen dwarf paladin. There is speculation that he fell to the Scourge after Uther's death, as he might have been a leading member of the Knights of the Silver Hand. This is at least partially confirmed when Alexandros Mograine refers to Korth'azz as "one of Uther's men".

Korth'azz likely represents the "Pale Rider of Death", based on his light green color scheme.

Ashbringer
Thane Korth'azz witnessed the enslaving of Alexandros Mograine by Kel'Thuzad. He later fought against the party Darion Mograine led into Naxxramas. He traded blows (and insults) with Brannigan Thundermaul until Brannigan was slain by Sir Zeliek. He then struck Castillian in the back of the head and used his fire magic to free Highlord Mograine from Castillian's freezing spell. He was finally defeated when Darion struck him down with the Corrupted Ashbringer.

Wrath of the Lich King
Thane Korth'azz survived his encounter in the first siege against Naxxramas in the Eastern Plaguelands (or was reanimated), and subsequently returns as one of the Four Horsemen in the newly relocated necropolis floating above the Dragonblight.

Ashbringer

 * Stuff a socking in it, Zeliek!
 * Stand down, ye dull-witted twirlybird!
 * Kiss me arse, ye soft-noggined nancy boy!
 * That'll do with the parlor tricks, magic man.
 * Oh no ye don't, boy!

Naxxramas

 * Intro
 * yell
 * yell
 * yell
 * yell
 * yell
 * yell
 * yell
 * yell


 * Taunt
 * yell


 * Aggro
 * say


 * Killing a player
 * say


 * Special
 * say


 * Death
 * say

Trivia

 * An unused NPC representing a modern version of Thane Korth'azz was added roughly at the same time as matching versions of the three other original Horsemen, all presumably meant to appear in World of Warcraft: Legion. He and these other NPCs didn't make it out of the Legion alpha stage.

Speculation
It is possible that Korth'azz didn't meet his final death, just like Baron Rivendare.