Which World of Warcraft expansion made Worgen a playable Alliance race? Cataclysm.
Cataclysm made Worgen a playable Alliance race. Released in 2010, the expansion added the Worgen of Gilneas alongside the Goblins, who joined the Horde, giving each faction a new race connected directly to Cataclysm’s story.
Worgen are humans afflicted by a savage wolf-like curse. Their starting storyline follows the fall of Gilneas, the kingdom ruled by Genn Greymane, as the curse spreads and the Forsaken invade. Players experience the transformation from human to Worgen before the survivors eventually enter the wider Alliance conflict.
Cataclysm also dramatically reshaped Azeroth. Deathwing’s return devastated large portions of Kalimdor and the Eastern Kingdoms, while the level cap rose from 80 to 85. The Worgen were therefore not introduced in a later expansion such as Legion, Shadowlands, or Dragonflight. Those expansions added other races, classes, zones, and systems, but the playable Worgen origin belongs specifically to Cataclysm.