Kortex was a protoss fleetmaster during the first great war. He and his fleet were at the battle of aiur but had to retreat due to the vast amount of zerg.
his fleet retreated to caroisis: a world the protoss colonized many years earlier. A few days later the zerg attacked and took the planet.
Kortex lost most of his fleet but managed to escape in his carrier wich later crashed in an area the zerg had not yet conquered and used the crashsite as his base of operations.
THE CLEANSING OF CAROISIS
Kortex and his surviving warriors activated a becon that let the protoss know he was there. a protoss fleet arrived and burned most of the landscape.
The area kortex was in was unharmed and he and his warriors were picked up by a group of arbiters.