The Messerschmitt Bf.109 was one of the first truly modern fighters of WWII. Originally conceived as an interceptor, the Bf.109 fulfilled multiple roles, as bomber escort, fighter-bomber, ground-attack aircraft, and reconnaissance aircraft. The final production version of the Bf.109 was the K series, or “Kurfurst.” Externally similar to the G series, it had a large number of internal and aerodynamic changes that improved its effectiveness and remedied existing flaws, which kept it competitive against rival fighters. Jagdgeschwader 77 used the last version of Bf.109 to fight in the Reichsverteidigung (defense of the Reich) during the last days of WWII, to slow the inevitable German defeat.