"Guardians are warriors forged in the Traveler's Light, a final hope in a universe falling into Darkness. Chosen from the dead by the Traveler's Ghosts, Guardians are those rare few able to wield the Light as a weapon. For centuries they have defended the City. But that defense cannot hold forever. Now, with the Darkness rising again, the time has come to retake our lost worlds. The Guardians who lead the way will save humanity - and become legend." that is a ghost fragment and in its words any race that is able to wield the traveler's light as a weapon so technically any race could be a guardian