Protector (Victory I-class)

The Protector was the flagship of Admiral Harkov. It was a Victory-class Star Destroyer. The Protector was one of the first ships that received the TIE Avenger starfighters. It was heavily involved in Admiral Harkov's defection, and evaded capture for a short time after the Admiral's demise. Eventually the Protector was hunted down by Imperial forces. Despite assistance from the Rebel Alliance, in the form of the Light Calamari Cruiser Warhawk, and several Corellian Corvettes and Escort Shuttles, and one of Harkov's Nebulon-B Frigates, the Akaga; the Protector was destroyed by Imperial starfighter forces, aided by Maarek Stele.

Source
Star Wars: TIE Fighter PC game.