The Drej are an alien species recently encountered by the Katana. They are based upon the antagonists from the movie Titan A.E. Though they have a roughly humanoid appearance, they are non-corporeal.
Though they are non-corporeal, the Drej appear to have soundly structured bodies with skeletal and muscle tissue. All Drej are pure plasma energy beings, glowing bright blue. However, they are still tangible beings and able to manipulate their environment. They are also able to regenerate lost body parts. It's rumored that instead of evolving on a planet, even a gas giant, they evolved on the surface of a giant and ancient sun deep in the unexplored regions on the far side of the JFS47 stellar nursery. This sun is also rumored to have three smaller suns orbiting it.
Like the Drej themselves, Drej ships and technology is comprised entirely of bright blue and gold energy, yet still tangible. It is possible to escape Drej structures by touching the surface with both hands close together and then moving the hands apart; this is thought to disrupt the energy flow just long enough for an agile person to escape.
As they have little mass yet massive amounts of energy, even their smallest ships can travel at high warp speeds. Their weaponry is a plasma wave attack that is similar in strength to that of a solar flare and difficult to defend against. Even metaphasic shielding has trouble forming a stable field when this blast strikes a ship. The energy residue can even disrupt most warp fields. Due to their energy based nature, phasers have little effect and torpedoes are easily vaporized by the energy sheathe the ship is normally shrouded in.
Because of the differences between the Drej and most races, they consider corporeal matter based entities to be a disease upon the universe and have all but exterminated dozens of different races. One of the hiding places of the survivors of these purges is a space station built over 90 thousand years ago hidden deep inside of a dangerous nebula where these survivors and their descendants eke out a meager living and hoping for the day that they can get revenge on the Drej.