In StarCraft, Tassadar is the Protoss military commander who leads the campaign against the Zerg on Aiur.
Tassadar is introduced as a Protoss executor sent to contain the Zerg threat on human worlds. His decisions become controversial because he uses energy-based attacks against Terran colonies, causing political conflict with Protoss authorities. Later, he returns to Aiur and joins forces with the templar Fenix and the dark templar Zeratul.
Tassadar is sometimes confused with Artanis, who becomes an important Protoss leader in later StarCraft II events. Zeratul is another central Protoss character, but he belongs to the dark templar and serves a different narrative role. Fenix is Tassadar's ally and a famous Protoss warrior, not the campaign's principal commander.
Tassadar's story culminates in a decisive assault on the Overmind. His actions also help bridge the traditional divide between the Protoss and the exiled dark templar.