The Guardian was the first Jet aircraft operated by the Krakabloa Air Arm. Developed from the airframe of the 'Defender' propellor driven fighter, it is rather primitive in design. Entering service mid way through the War of Union its arrival prompted the Wright Isles to begin their own jet programme.

The Mk1.b featured a redesigned fuselage to accommodate the new more powerful engine. More than able to outfight the first 'Nipper' aircraft of the WIADF, the Mk.1b was also capable against the later 'Nipper 2'. Unfortunately it's small size meant that the Mk.1b did not have a great amount of room for fuel, so it was mostly used in the short range interceptor role. All Mk.1b aircraft were new builds rather than being converted for earlier marks.