He is a wealthy man with receding gray hair which eventually faded to gray wisps with age, and a "weak" chin.
Pasteur refused to drink alcohol, saying "there's no such thing as just one for me. Not anymore."
Ailin Pasteur was an Umojan ambassador. In 2478, he and his daughter, Juliana, paid a visit to Korhal Senator Angus Mengsk, already known then for his anti-Confederate views. The meeting was interrupted by a team of neurally resocialized Confederate marines, disguised as a corporate death squad. The team was defeated by the Mengsk family's security team.
Pasteur agreed to provide Umojan aid for Mengsk's new initiative – a secret armed struggle against the Confederacy. Umoja secretly shipped this material to Mengsk for years, which were used in ambushes and bombings, killing hundreds of Confederate troops.
Pasteur attended the Close of Session speech, where Angus Mengsk denounced the Confederacy and ripped down their flag. He confronted Arcturus on his way out for having left his family and his father's cause for the Confederate Marine Corps. Ailin was disgusted at the teenager's actions.
Ailin and Juliana continued to make regular trips to Korhal to see Angus. In 2481, Juliana reunited with Arcturus. The union produced a son, Valerian. However, Mengsk was serving in the Confederate Marine Corps, and Juliana insisted on keeping the existence of the boy secret as long as Mengsk remained a marine.
By 2489 Arcturus Mengsk had left the Marine Corps and become a successful prospector, and the Rebellion of Korhal became public knowledge as Angus Mengsk declared Korhal independent from the Confederacy. Juliana chose this moment to try to reestablish contact with Arcturus. Ailin Pasteur sent him a communication, telling him to come to Umoja as quickly as possible.
When Arcturus Mengsk arrived at Ailin Pasteur's home, Pasteur treated him coldly since he had abandoned his daughter. The meeting didn't go well, especially since Mengsk was surprised to find he had a seven-year-old son. However, Mengsk remained at Pasteur's house as he sent news to his family.
The return message, however, was unpleasant. Achton Feld reported that assassins had murdered Angus Mengsk and his wife and daughter. Arcturus Mengsk became consumed by revenge against the Confederacy.
Pasteur, whose life had been previously saved by Angus Mengsk, offered Arcturus his support in revolutionary activities. As a voting member of the Umojan Ruling Council, he appointed Arcturus general and leader of the Rebellion of Korhal.
The Sons of KorhalEdit
Two years after the assassination of the Mengsk family, the Umojans had given the Rebellion great quantities of material aid, even including tanks. The Confederacy retaliated by destroying Korhal with a nuclear barrage.
Pasteur and Mengsk watched the scene from Umoja. After the shock passed, Mengsk renamed the Rebellion the Sons of Korhal, and Pasteur handed over a stolen Confederate battlecruiser to Mengsk, a year after it had been acquired by the Protectorate. Mengsk named the ship the Hyperion, which the Sons of Korhal used as a mobile headquarters.
The Terran DominionEdit
By 2500 Arcturus Mengsk was emperor of the Terran Dominion. He traveled to Umoja with a fleet of Dominion capital ships commanded by General Edmund Duke in order to make his first visit there as emperor and see Valerian. He had to negotiate passage with Pasteur, who forbade him from sending the capital ships close to Umoja. Mengsk had to travel in a gun cutter.
Shortly after landing, Arcturus Mengsk's group was attacked by the Confederate Resistance Forces, which damaged the cutter and did serious damage to Pasteur's house, his staff, and the defenders. The Confederates also scrambled communications, cutting them off from Mengsk's fleet. When Pasteur demanded Mengsk tell him what was going on, Mengsk replied that he could defeat the attackers, and told Pasteur to take his daughter to his safe room.
With the help of his son and warrior Master Miyamoto, Mengsk held off the invaders long enough for Duke's ships to rescue them – Duke had ignored Umojan instructions to stay beyond the outer markers. The Protectorate had to once again order the ships away from Umoja.