France and Soviet Union

On 1 March 1940, Ludwiger was appointed commander of the 83rd Infantry Regiment of the 28th Infantry Division, with which he took part in the Invasion of France.^[2][3] Following Operation Barbarossa, he was awarded the Knight's Cross of the Iron Cross on 15 July 1941, and was promoted to Oberst on 1 September 1941.^[2][3] Due to the heavy casualties his regiment (and the division as a whole) suffered while fighting in the Battle of Moscow, the 28th Infantry Division was moved to occupied France to refit as a Jäger division on 1 December.^[3] The 28th Jäger Division was sent back to the front in southern Ukraine, where it participated in the Battle of the Kerch Peninsula in the Crimea and in the Strait of Kerch.^[3] During his award ceremony, he met his future superior, Hubert Lanz, and his future subordinate Harald von Hirschfeld.^[5]

Yugoslavia

Ludwiger was posted as commander of the 704th Infantry Division in Yugoslavia on 20 February 1943.^[2] The division was later (1 April 1943) renamed to 104th Jäger Division and Ludwiger assumed his post on 3 March 1943, while within the next month, he was promoted to Generalmajor.^[6]

Ludwiger was quite active in the anti-Partisan operations. In particular, he was placed in command of a unit consisting mainly of the 724th Jäger Regiment and a Bulgarian regiment, designated Kampfgruppe von Ludwiger (Battle Group von Ludwiger).^[7] Aided by the Italian Taurinense Division, Kampfgruppe Ludwiger was tasked with the obliteration of armed guerrillas in the area of Montenegro, mainly Chetniks and Tito's communist partisans. This campaign was launched on 20 May under the codename Fall Schwarz (Case Black).^[6] But, as partisans deliberately avoided open battles with the well-equipped German forces (at least in Ludwiger's sector), the overall action of the Kampfgruppe returned rather poor results. Subsequently, the unit was dissolved on 9 June and Ludwiger with his staff returned to Požarevac.^[7]

Of course, Ludwiger didn't quit his activities concerning the suppression of partisans. But with chances of extermination of the partisan forces themselves being slim, in the meanwhile Ludwiger launched a terror campaign against the civilian population.^[8] Specifically, he implemented the typical 50:1 reprisals ratio, which ordered the execution of 50 civilian hostages for every German killed by partisan activity. As a result, in two months' time, from 1 April to 1 June, Ludwiger's superior, supreme commander of Military District Serbia, General Paul Bader, was virtually flooded with Ludwiger's requests for reprisals, but he nevertheless authorized them. In total, 500 civilians were killed in reprisals for the murder of 8 German soldiers and 2 Serbian mayors from partisans, while numerous villages were looted and torched.^[8]

Greece

Upon completion of Operation Black, 104th Jäger Division was ordered to move to Western Greece. While on march to Agrinio, on 10 July, the 2nd Company of the division's Pioneer Battalion was ambushed near the Trichonida Lake by Greek guerrillas, who were reported to be dressed like British soldiers. Two officers and 16 soldiers were killed, while another 20 were wounded and several vehicles were destroyed.^[9] The next day, an officer was killed from a hand grenade tossed on his vehicle. Ludwiger, installing his headquarters in Agrinio, applied to carry out his usual reprisal tactics against civilians, but this time his request was rejected from the staff of Army Group "E", as the Germans initially tried to maintain good relations with the Greek population. Despite this, German forces razed a village near Nafpaktos and executed 12 "suspicious gangsters".^[10]

After the Allied invasion of Sicily, Italian forces signed an armistice with the Allied troops. The Germans were prepared for this possibility and launched Operation Achse to forcibly disarm Italian troops in southern France and the Balkans. The 1st Company of the 724th Battalion of Ludwiger's division was ordered to disarm the Italian garrison in Kefalonia along with the 1st Mountain Division, something that resulted in one of the largest executions of POWs to be committed during World War II: the massacre of the Acqui Division in September 1943.^{[Notes 1]}

Ludwiger was promoted to Generalleutnant on 1 January 1944.^{[citation needed]} As of by August 1944, Ludwiger's forces continued the reprisals against the Greek population, now aided by SS divisions.^[11] Ludwiger wrote in his report that

With the permanent destruction of the villages in all the areas they passed from, but mainly with the decisive burning of the communistic centre of Karpenisi, the partisans were deprived from numerous possible shelters.^[11]

Ludwiger and the surviving elements of his division, which had suffered heavy casualties in the Balkans, were captured towards the end of the war.^[1] His successor in command of 104th Jäger Division, Generalleutnant Friedrich Stephan was captured as well and was shot in Ljubljana along with three other generals without trial from Yugoslav partisans in early June.^{[citation needed]}