Marcus Aron Brandt, was Human male who served during the Great Galactic War initially as a Republic trooper of the Republic Special Forces Division assigned to Infantry unit 326 known better as "Havoc Squad", and the subsequent conflicts that followed, the Cold War and Galactic War, the galaxy-wide conflicts against the resurgent Sith Empire as a mercenary after being forcibly removed from military service following the battle of Alderaan for unknown reasons.
Hailing from Corroth, a planet in the Colonies, Marcus Aron Brandt was born to a Human couple. His father took a young Marcus on an annual fishing trip to a lake on Alderaan until he had fallen ill, which prompted a teenage Marcus to forge documents and join the Republic Army at sixteen.
Great Galactic War
Sometime later, Brandt, now a private, was a assigned to 3rd Battalion, 27th Infantry Regiment and fought in a battle against the resurgent Sith Empire in which his entire unit except himself and two others were killed in action. Showing promise over the next few years, he was tested and accepted into the Republic Special Forces Division and inducted into Infantry Unit 326 known better as "Havoc Squad" under Captain Jace Malcom. He was later promoted to corporal.
Stationed and havoc on a peaceful world
I've been in quite a few battles and obviously seen my share of war, killed my share too, but Alderaan—specifically the skirmish at the base of the Juran Mountains, by far, was the most savage and adrenaline pumping fight I've been a part of. I'm proud to have done my part.
—Marcus Brandt, on the battle of Alderaan
In 3667 BBY, Brandt and Havoc Squad were stationed on Alderaan—the tranquil world many considered the very soul of the Republic, where numerous soldiers of the Republic Military went to rest from the frontlines of the war and recovered from exhaustion and injuries sustained on battlefields far away. However, Alderaan's reputation for being a spiritual center made the peaceful world an enticing target for invasion by the Sith Empire, which led way for a plan to destroy the planet and capitalize on the damage it would cause to morale for Republic forces.
While Brandt and the rest of Havoc Squad remained on Alderaan's surface alongside other recovering Republic ground forces, the Republic Navy withdrew from the planet to pursue a distress call. While away the planet was besieged by a massive Sith invasion led by Sith Lord Darth Malgus. that decisively obliterated local defenses, leveled cities, killing thousands and with relative ease, seized the world.
Unaware there were any Republic forces planetside, the remaining forces had gone to ground, hiding themselves in the surrounding mountains and forests while launching a guerilla campaign against the invading forces. Upon discovering that the Sith were on the march to Alderaan's capital city, it was put out that Havoc Squad would perform an all-out assault. The troopers of Havoc Squad, many of whom were still recovering from injuries, positioned themselves on a ridge outside of Alderaan's capital in the Juran Mountains in hopes of preventing the attack on the city—a goal that was widely perceived as a suicide mission. Despite the obvious danger, Brandt followed the man into battle, jumping from a ridge into the fray of battle. He carried numerous which he proceeded to use on the war droids, he then tackled a lightsaber-wielding Sith to the ground before shooting him. Marcus continued to fight even after it seemed the tide of the battle had turned when Malcom was knocked unconscious by Malgus's Force lightning, but he received a boost in morale once the Jedi Satele Shan arrived and turned the fight back in Republic favor, tossing the captain a rifle so he could get back in the fight. Eventually the battle was won and Havoc Squad was shipped off-world.