As a child, Arcturus was constantly in the shadow of his father Angus, who was a famous senator of Korhal who constantly railed against the Confederacy. However, Arcturus himself showed much promise of leadership, even at an early age, easily able to make other people do what he told them, either through intimidation or charm.
At the age 17, he snuck out of the Korhal Academy and into his father's highly guarded summer villa, and went through undetected by everyone except Achton Feld, head of security. Before Achton could take action against Arcturus, however, the villa was attacked by armed men. Achton lead Arcturus, Arcturus' mother Katherine, and his sister Dorothy, as well as Ailin Pasteur (a senator from the planet Umoja) and his daughter Juliana into a safe room until Angus and his security cleared out the armed men.
Days later Arcturus was escorted back to the academy to finish his last semester there. While completing school, he developed a faint relationship with Juliana through mail, although he didn't think much of it at the time. Towards the middle of the semester a recruiting team from the Confederate Marine Corps showed up to take applications, and Arcturus became interested. After graduation he enlisted in the Marines, much to his family's dismay.
Arcturus served in the military for over a decade, after which he became a prospector. The day after he struck a huge vein of rare metal, however, he was called to Umoja by Ailin Pasteur. There he learned of his son, Valerian, whom he had conceived with Juliana while on military leave. He thought of Valerian as a weakling, and attempted to whip him into shape. When he was to announce his son to the rest of his family, however, he discovered that Confederate forces had killed his family to quiet his outspoken father. After this, Arcturus left his family on Umoja and began his campaign against the confederacy. Shortly thereafter however,the entire population of Korhal was killed by over one thousand Apocalypse-class Nuclear Missiles, rendering the planet a molten, charred waste. Arcturus had left the planet days before, however, and after this he created the Sons of Korhal to combat the Confederacy.
Now the Emperor of the Terran Dominion, Arcturus returned to Umoja to see his son and wife. Juliana had contracted a rare form of cancer and was soon to die. The day Arcturus reached Umoja, however, it was attacked by ex-confederate soldiers, and he survived only because of Edmund Duke's interference. His wife died 18 months after the attack, after which Arcturus took Valerian and made him his heir.