Here is a short bio on General Markulj:
MARKULJ, Ivan - NDH General (born in Mostar Feb. 11, 1889 - executed in Belgrade on ? September, 1945). Army officer in the Austro-Hungarian and Royal Yugoslav armed forces, he was a Colonel at the the time of the Yugoslav Monarchy's capitulation. He volunteers for service in the newly founded NDH (Independent State of Croatia), and is named commander of the Varazdin Infantry Regiment. In June of 1941 he is named commander of the "Croatian Legion" - the 369th Reinforced Infantry Regiment (Croat), a unit of Croatian volunteers raised to serve within the German Wehrmacht on the Eastern Front. He took the regiment through training in Germany begining on July 21, 1941, and to the Eastern Front where already in October 1941 it had its first battles with Soviet forces. In early February 1942 the regiment participated in the battles around Samara. In June 1942 Markulj is promoted to General, withdrawn from the regiment and given the position of Commander of the City of Zagreb. In late 1943 he becomes the commander of III NDH Corps with its headquarters in Sarajevo, and remains in this position until the NDH forces withdrawl from the area in April 1945. He surrendered to the British in May of 1945, and was extradited to Yugoslavia. The Supreme Military Court of Yugoslavia in Belgrade convicted Markulj in September of 1945 and sentenced him to death.
Source: Based on short biographical essay by Milan Pojic and Mato Rupic, Croatian State Archives. Published in the book "Tko je tko u NDH". English translation by Allen Milcic.
Fangio: I believe the photo you have posted was originally published in the book "Hrvatsko domobranstvo u drugom svjetskom ratu - I. dio" by Ivan Kosutic. I am uncertain if it actually is Markulj - the photo I have of him in Heer uniform on the Eastern Front (found in "Tko je tko u NDH") looks nothing like the photo from the Kosutic book. I'll try to get a scan of the photo I have for you to view.