The 21st Caspian Marine Tactical Operations Squadron, or Wildcats, was a Marine Aerospace Division unit of the Union Defense Force. It was one of the first six MAD squadrons formed in the second year of the Crest, and it was frequently deployed on rotating assignments to the Union's frontier in the early days of the SONG network. The pilots were trained in the use of A-wings, and Z-95 Headhunters, but had been equipped with and were getting accustomed to the new Z-100 Centurions.