Dalus was the Mentor Cêpan of Zane, Lexa's younger brother.
Dalus would have been assigned to Zane when he was around the age of eleven. Lexa, questioned his qualifications from the start and felt that he was 'too new and too green' to be able to handle Zane who was headstrong and needed an authoritarian figure. Lexa had complained to the Lorien Defense Academy higher ups who claimed that the bond between them had already been created and separating them would damage both of them.
He was described as meek, with a quite voice that you had to learn to hear.
It was said that Dalus saw promise in Zane, not as a student like everyone else, but something he could exploit to claim credit and better his reputation. It was also known that those high up in the LDC would place bets on Garde races and other trials which gave Dalus the opportunity to make a hefty profit. For these reasons Dalus would push Zane hard to reach his full potential.
After Zane's death, likely due to the fact that Dalus had pushed him to fly at the speed he was when he crashed into the Kabarak supply ship, the LDA send him to a remote Kabarak but would not tell Lexa where (The Navigator).