Gul'dan represents the 
Warlock class in Hearthstone: Heroes of Warcraft. The first Orc to become a Warlock, and the one credited with creating the Horde. In his search for more powerful magics, he led the orcs into demonic enslavement by the Burning Legion. He led the orcs to conquest Azeroth in the First War and created the first Death Knights during the Second War. Gul'dan's skull is just as famous as he is. A part of his soul still lingered in his skull and it would whisper to anyone who held it. It was used to destroy the Dark Portal, corrupt the forests in Felwood, and Illidan Stormrage absorbed its power turning himself into a half-demon. Illidan held possession of it until his death in the Black Temple.
Warlock is the only class so far with a minion (
Lord Jaraxxus) that replaces the hero and give a new hero power.
Warlock Hero Powers
Template:Class hero power table
INFERNO! is the version of the Hero Power that Warlocks get when they summon Lord Jaraxxus.
While Life Tap may seem like an unworthy trade to newcomers, the ability to gain card advantage is very strong in any CCG, making it one of the better hero powers in the game.
Warlock Spells
Template:Class spell card table All classes can also use spells in their decks which do not have a defined class. See Spell cards.
Warlock Minions
Template:Class minion card table All classes can also use demons in their decks which do not have a defined class. See Demon cards.