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 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.

Like the Drej themselves, Drej ships and technology is comprised entirely of bright blue 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.