Though they were cousins, Aldius and Rellian Shacklam acted together like brothers, for emotionally, they were.
On Tatooine, Aldius came to live with Rellian and his family at the age of 6, when his parents were killed by tusken raiders.
Rellian was only three years older, so he and Aldius became quite close as they shared the same experiences with the same things.
However, when Aldius was 11, he was taken away to become a Jedi, something which Rellian refused to become; he enjoyed his simple life, and tried to persuade Aldius to stay, but to no avail. Aldius told him that if he were to become a Jedi, he could come back to Tatooine and give Rellian and his family a better life.
Helpless to stop Aldius from leaving Tatooine, Rellian sank into a deep depression, and it was then that his own force sensitivity manifested itself violently, his anger overtaking him as he killed his parents.
Had it not been for a Sith Lord that was present nearby at the time, Rellian would have ended up homeless, and possibly dead. Rellian was taken away to Korriban, where he was put through the brutal trials to become Sith. His depression still deepened, as he missed Aldius and felt great regret for killing his mother and father.
This, combined with the Sith trials, emotionally broke Rellian. He became cold, calculating, and ruthless; traits that gained him a Sith master. He discarded his old name, perhaps for the symbolic aspects of it, and renamed himself Irritius.
At the age of 18, Irritius became a Lord. And then, at the age of 24, having killed his master, Irritius became a Darth. Very shortly after this, Irritius took on an apprentice.
Two months into his apprentice's training, Irritius decided he would take his new charge to Tatooine, where, as he told his apprentice, he learned "the truth of things."
By either insane coincidence or perhaps fate, Darth Irritius noticed a face in a Tatooine cantina that he could barely, make out, but recognized.
It was Aldius. Irritius took his apprentice outside, and waited for Aldius to leave the cantina. When Aldius emerged, Irritius grabbed him and took him into the shadows.
Taken by surprise, Aldius could tell by the type of clothing that Irritius had that he was a Sith. The two might have fought, but Irritius removed his helmet, and Aldius recognized him as his beloved cousin.
A chance meeting such as this and the circumstances of who was who convinced Aldius to follow Irritius to his personal ship, where they could converse safely and privately.
On the ship, Aldius explained that he had been looking for Rellian, unaware of his Sith ties. Irritius, though mostly emotionally cold and deprived, showed what little happiness he could feel at that time.
Irritius, having both the love of his cousin and his own way with words, was able to easily convince Aldius to leave the Jedi, and join Irritius as Sith.
Using his status as a Darth, Irritius was able to circumvent the standard procedures for new Sith, and took Aldius as his new apprentice, discarding his previous one.
The two were reunited at last, something that Irritius did not expect to ever happen. The strong bond between the two caused them to agree that they would not follow the usual Sith tradition of one killing the other in the Master-Apprentice order.
Together once more, they were prepared to take on whatever the galaxy threw at them.