According to Britannica, Carol II wanted to emulate the infrastructural progress he perceived to have been accomplished by Mussolini. When he became King of Romania in 1930, he proceeded to erode democratic processes and give himself absolute authority. Meanwhile, he led a scandal-ridden life full of alcohol and affairs that sparked his temporary replacement by his son Micheal I (via TheFamousPeople). Despite these exceptionally dictatorial actions, Carol maintained an alliance with France and Britain in addition to his efforts to gain German favor. Hitler, concerned and incensed by the potential of resource-rich Romania as an enemy, sought to punish the King’s seeming indecision (via History Today). 

In 1940, Germany found itself as the arbitrator of a border dispute between Romania and Hungary, stemming from the latter trying to claim the former’s territory as the Soviet Union and Bulgaria had done previously. In order to prevent war between two potential allies and to weaken Carol’s government, the Germans proposed the effective splitting of Transylvania between the two parties (via Oxford Reference). While not ideal, German insistence that these borders would be respected in the future led Carol to sign the agreement (via History). The Romanian public was enraged by this further humiliation and revolted. To avoid escalation, Carol ceded his power to other figures, but they only proceeded to force his full abdication, ally themselves with Hitler, and again replace him with his son (via The New York Times).