Dev had been born with Force potential, and when he was enslaved by the species known as the Ssi-ruuvi, he was forced to use his powers for their dark purposes. The son of a female Jedi apprentice, Dev was raised on Chandrila. His father was unknown, and Dev would never find him. Although not a full Jedi, his mother still trained Dev in the ways of the Force.
At first he learned awareness and communication, but before he could learn more, the great Jedi purge began. The Empire was intent on destroying the Jedi, making sure their flame left the galaxy forever. This forced Dev's family to run to G'rho, a planet so isolated it was highly unlikely that they would be found. But in the end they were found, although it was not by the Empire. The Ssi-ruuvi empire came to G'rho, and enslaved and murdered the population. At this time Dev was barely ten years old, although he was small for his age. He fled and hid in a ravine, where through the Force he felt his mother's essence disappear. After that, Dev was found, but not killed.
The reptilian Ssi-ruuvi took Dev to their home planet, Lwekk, where they uncovered his Force abilities. They knew he would be of great use to them, and so for the next five years trained him in their language and culture, while at the same time brainwashing him. After this period, Dev was very like a native Ssi-ruuvi, and had by then taught his new masters much about the human race.
The Ssi-ruuvi wanted to use Dev to use his powers to locate and calm down people they wished to use for 'entechment'. Entechment was a process by which the Ssi-ruuvi would be able to transfer a human's brain patterns into a huge battle droid. They had been experimenting with the process for years, and now they felt they would be able to use it to conquer the galaxy. The Ssi-ruuvi told Dev that entechment took all your pains and worries away, and this convinced him so much that he longed to be enteched himself. Indeed his master, Firwirrung, had promised to free the boy of pain personally, and place Dev's brain patterns into one of the battle droids he wanted so.
Eventually, the Ssi-ruuvi came to the planet Bakura. They arrived shortly after the destruction of the second Death Star, and it was when at Bakura that Dev felt the presence of another Force user, only this one was much more powerful than he was. He hoped it was an actual Jedi, one who could teach to release the potential he knew he had. He started having feelings that had long ago been buried, and even the 'renewals' that Elder Sh'tk'ith gave him did not drown out their calls.
The hope to be a Jedi and join the light side became a reality when Dev met Luke, the Jedi whose presence he had felt. At first Dev helped his masters to capture Luke, but then answered his true calling and helped the Jedi Master to escape. He killed many Ssi-ruuvi, but suffered a fatal blow before he could flee the Ssi-ruuvi ship Shriwirr. In accordance with the Jedi training he had received, Dev went into a healing trance, and was aided by Luke and Alliance medics. But his wounds proved to bad, and he eventually died.
Dev may have died, but it was a noble death, one his mother would have been proud of. In death Dev could once again be with his mother, as he became one with the Light Side.