Thrax is the son of Rita Repulsa and Lord Zedd who appears in the episode "Once a Ranger". It seems Thrax inherited most of his appearance from his father, due to his physical appearance and his Z-Staff. Also, his powers seem to be similar to those of his father. His mother's appearance isn't apparent, except that he has a part humanoid face (similar to Grimlord from VR Troopers), and torn cloth-like orange ornaments wrapped around his horns. One similarity to his mother is that he too was imprisoned in a space dumpster. His jawbone resembles that of his uncle, Rito Revolto and has a skeletal spinal column, a combination resembling his father and uncle. His shoulder pads and chest armor are similar to Zeltrax from Power Rangers Dino Thunder.