From 2026 until 2035, Samantha served in the Concordian Armed Forces. However, in 2035, she was abruptly banished by her brother, Jaxson Dunwall -- who had become the Embattled Governour of Domi Concordia after their father had passed. Unknowing why she was resented by her brother, she immediately fled her homecountry and became a citizen of San Locura. There, she took a new identity as the Midnight Samurai, and founded the private military company Nightfall. When Jaxson was supposedly killed in the Campaign Against the Covenant -- and her older brother, Isaac, had become the new Concordian leader -- she gained access information into the Statocracy's virtual databases and servers. Such a success was only shrouded by the chaos of Isaac somehow ascending to the rank of Embattled Governour. Within the same year, however, Isaac was killed by his and Samantha's nephew -- Alexander Dunwall. Despite her siblings both being dead, her hatred for her homecountry still remained.Through the 2040s, Samantha hacked the Stratocracy's servers and databases with the access codes under the hacker name "Chron-X88". Even through several attempts at new access codes by the Concordians, she was still able to break through and steal information and documents, such as plans for the Vaella Complex and schedules. In 2049, however, the entire system was reconfigured and her hacking was too incompetent to bypass the new firewall, thus permanently retiring the "Chron-X88" persona. In the mid-2050s, however, she was approached by Extrema Caeli -- a stateless military organization that had previously initiated the Mercenary Wars. They wished to contract 350 Nightfall mercenaries for their own use. Seeing as they would be targeting Domi Concordia numerous times in the coming years, she agreed -- and even contracted her own services in hopes of getting closer to the current leading Dunwall.
Through her persona as the Midnight Samura, she attempted to assassinate her nephew on Brezniik XXIII, 2058. However, this plan was foiled as Alexander Dunwall awoke right before being struck by her katana. The two battled in his penthouse, until she escaped by jumping out of the bedroom window. The two Dunwalls dueled again during the Siege of the Vaella Complex, when Alexander agreed to have a one-on-one battle with her. However, she was bested yet again, and her helmet was destroyed, thus revealing her identity to him. Before she could be truly defeated, she escaped once more by the use of smoke.
After the defeat and dissolution of Extrema Caeli at the end of the Vanburgh War, Samantha Dunwall had gone into hiding. Sometime between 2058 and 2066, she created a deadly biological weapon that could could kill humans in a matter of seconds. After creating a large quantity of this bioweapon later known as the sarkatroei virus, she came in ownership of a cargo plane. It is likely that she knew of the wherabouts of a plane Extrema Caeli had stolen and hid in the past. After sometime of preparation, Samantha loaded the cargo plane with containers of the sarkatroei gas agent and piloted it toward Vinylla City, Concord, Domi Concordia -- where she had hoped to crash it into the Vaella Complex, and thus unleashing it across the entire city.
However, her plan backfired when one of the containers began to leak the gas into the plane. This soon killed her, deforming her and her corpse. The plane then crashed into a small Concordian town named Arvaltown, thus causing the Aurea-Luxuria Calamity.