Short answers, pulled from the story.
Ion Antonescu was a Romanian military officer and marshal who served as Prime Minister and Conducator of Romania during most of World War II. He led Romania into an alliance with Nazi Germany, joining the attack on the Soviet Union in 1941, and his regime was responsible for policies that caused the deaths of as many as 400,000 people, most of them Bessarabian, Ukrainian, and Romanian Jews as well as Romanian Romani.
The National Legionary State was a regime formally proclaimed on the 14th of September 1940, created as a coalition between Antonescu's military dictatorship and the Iron Guard, a fascist and antisemitic movement led by Horia Sima. The Iron Guard became the only legally permitted political party in Romania under this arrangement. The partnership was short-lived; Antonescu suppressed the Iron Guard following the Legionary Rebellion of January 1941.
Antonescu's regime combined pogroms, mass murder, and ethnic cleansing with deportations to occupied Transnistria, a territory Romania occupied from August 1941 onward. Large-scale atrocities included the Iasi pogrom and the Odessa massacre, ordered by Antonescu as retaliation for a bombing that killed Romanian officers. The regime showed leniency toward most Jews in the Old Kingdom and ultimately refused to adopt Germany's Final Solution, while independently causing the deaths of as many as 400,000 people.
On the 23rd of August 1944, King Michael I summoned Antonescu to the Royal Palace, demanded Romania exit the Axis alliance, and had him arrested when he refused. Antonescu was handed to Soviet forces, interrogated at Lubyanka prison by SMERSH operatives including Viktor Abakumov, then returned to Romania in spring 1946. He was convicted of war crimes, crimes against the peace, and treason at a People's Tribunal and executed by firing squad on the 1st of June 1946 at a site outside Jilava known as the Valley of the Peach Trees.
Antonescu met Hitler on at least nine occasions between June 1941 and August 1944. Hitler reportedly came to regard Antonescu as the only trustworthy person in Romania and the only foreigner he consulted on military matters. American historian Gerhard Weinberg wrote that Hitler was more consistently favorable toward Antonescu than toward any other leader he met except Mussolini. The two communicated through Hitler's interpreter Paul Schmidt, since Antonescu spoke French and Hitler spoke only German.
Romania, as a junior Axis partner that was never occupied by the Wehrmacht, retained a degree of political autonomy that allowed Antonescu to make independent decisions. His regime prioritized plunder over systematic killing and showed leniency toward most Jews in the Old Kingdom. Germany's Ambassador Killinger pressured Antonescu to deport Old Kingdom Jews to Polish death camps instead of Transnistria, threatening to reduce arms supplies, which constrained but did not fully determine Antonescu's choices.