Alexandus started his ascension in the Sith Academy on Korriban. Little is known about his life beforehand, as public Imperial records were wiped after his escape from the Academy.
Arriving on the planet's surface, Alexandus was immediately and constantly berated by his instructors. Lessons at the Academy focused heavily on martial skill with a lightsaber, as well as smaller lessons on knowledge of the force, ability to utilize pain to feed one's force ability and tactics in combat.
When it came to skill with a lightsaber, Alexandus never excelled. He was constantly beaten by other students, which caused him to be constantly beaten further by his instructors for his failure. These beatings happened daily, and Alexandus never recovered mentally from the abuse.
Where he failed as a student of martial skill, he in turn excelled greatly with his force abilities. Alexandus learned to use the force to push, crush, persuade and use lightning to great effect, outperforming even his instructors before they would physically beat him into submission. Greater still was Alexandus' abilities to use tactics to his advantage. When engaged in combat scenarios, Alexandus was able to use his students' strengths to win the day, each and every time. Even when the odds were stacked against him, Alexandus' knowledge of strategy allowed him to come out the victor. Most of his victories, especially ones against his teachers, caused him to be tortured.
Duel vs. Arthammas
One of the final times Alexandus was tested in the Sith Academy, he was forced to duel against the teachers' prized student, another Sith Pureblood named Arthammas. Where Alexandus faltered in skill with a blade, Arthammas was exceptionally gifted. The two were pitted against each other as rivals on numerous occasions. This final session of fighting, the students' were forbidden from using force abilities, being told to rely only on their strength and skill with a blade. Arthammas' assault on Alexandus was relentless. Feeling that he was going to be beaten to death, hearing the instructor urge Arthammas to assault him with all of the force he could muster. Alexandus lashed out with the force, stopping Arthammas from moving. When the instructor yelled at Alexandus to stop using the force, Alexandus snapped his instructors neck. Continuing to hold Arthammas, Alexandus snapped both of his knees and elbows, furthering to his ankles and wrists, severing them all from the rest of his body or snapping them in half. Afterwards, Alexandus made a run for the spaceport, stealing an Academy shuttle and fleeing Imperial space as fast as he could. He never looked back nor did he look to see if he had killed Arthammas.
Joining the Imperium
After fleeing the Sith Empire's Academy, Alexandus continually ran, hopping from planet to planet until he made his way to Solaria. Initially fearing he had stumbled upon an Imperial world that was not on their territorial charts, It was soon discovered that he located the Sith Imperium, which was a very different entity from the Empire. He was welcomed into their society and taught the One Sith Code at the Academy, which resonated with him. Learning of the Emperors of old and their sacrifices for the Imperium, Alexandus dedicated himself fully to preserving the Imperium and defending it. Alexandus graduated with honors and was taken as an apprentice under Darth Luthandalur.