Jo Zentezi (May 12, 1912 - December 27, 1960) served as Chief Justicar of The Aurelian Union from August 1944 until his assassination in December 1960. Jo served during the Second Aurelian Civil War, with much of his term focusing on rebuilding the fallen International States of Borealia and quelling the increased anti-government sentiment following the war. CJ Jo graduated from the Justicar Academy in June 1944 at the top of his class in diplomacy and challenged the then current Chief Justicar Hal'kalen for the position. CJ Hal'kalen conceded his seat in August, following the long standing tradition of transferring power during the month of August.

Jo was born in the city of Aldan in the Artezia region of Borealia. Throughout school, Jo actually performed poorly academically but passed all five rounds of the NPQT with a high mark. He was granted a conditional entrance into the Justicar Academy where he earned Rank One in the Diplomacy Attribute. During Jo's time in the academy, war raged in the north between the Union and the newly formed IRSB. Artezia, a primary instigator of cessation from the Union, was his homeland. Originally desiring to be a diplomat in the World Council, Jo was approached by CJ Hal'kalen, having served the maximum of fifteen years, and convinced Jo to challenge him on his tenth year. Jo challenged Hal'kalen two days after graduation from the Justicar Academy and the country began a new election with the Challenge of 1944. Jo competed with Yel'eni Mar'tei (Au're, economics), Forr Dara (Haldenia, law), and Yuzi Ulenka (Kara, military). Jo was originally met with extreme resistance, with Yuzi Ulenka leading. To regions that remained in the Union, Jo was seen as an IRSB sympathizer and to the former IRSB, Jo was seen as a traitor and an Au'ren puppet. However, Jo's charisma and tact conveyed a sense of unity among those around him. Jo claimed to be neither from Au're or the IRSB, and instead from the Union. Playing upon the sense of unity felt during the First World War, Artezians and other former ISRB states began to see that they needed the Union, and that the Union needed them. After this, Jo gained immense support from former IRSB states and the Union as a whole. The election concluded with Jo crowned Chief Justicar, who claimed a margin of 10% against the second runner up Yuzi Ulenka.