In 1941 a Croatian volunteer force was established by the Germans to fight against the Soviets. This force included an air wing in the 15. (Kroat)/JG 52. At first this Staffel used the Me-109E-7 but in 1942 they converted to the Me-106 G-2 and later to the G-6. 
In 1944 the Staffel re-equipped with the G-10 and continued to fight at the side of the Luftwaffe until the end of the war.

At the beginning the aircraft wore standard German markings with the Croatian red/white shield under the cockpit. From the end of 1944 the shield was moved to the tail and the aircraft carried a modified German cross, actually the cross of a 11th century king.

Me-109G-2 of the 15. (Kroat)/JG52 (Source: Wings of Fame 11)

Me-109E-7 of the 15. (Kroat)/JG52 in 1942 (Source: AJ Press Monografie 50: Messerschmitt Me-109 Cz. 6)

Me-109G-2 of the 15. (Kroat)/JG52 in 1942 (Source: Sojusznicy Luftwaffe Cz. 2)

Me-109G-6 of the 15. (Kroat)/JG52 in 1942 (Source: Sojusznicy Luftwaffe Cz. 2)

Me-109G of the 15. (Kroat)/JG52 (Source: Wings of Fame 11)

Me-109G of the 15. (Kroat)/JG52 in 1942 (Source: Sojusznicy Luftwaffe Cz. 2)