Katrina Turner is a level 70 NPC located in Gadgetzan in the contested territory of Tanaris. She gives you information about the arena vendor in Area 52 named Vixton Pinchwhistle.
She is likely a tribute to Tina Turner, who played a character from Mad Max: Beyond Thunderdome, as the Arena in Gadgetzan is also likely a tribute to the arena from that movie.
See List of Tanaris NPCs.