Thrax

Thrax is the son of Mighty Morphin Power Rangers villains Rita Repulsa and Lord Zedd, and the grandson of Master Vile. He appears as the main villain in the "Once a Ranger" episodes.Thrax inherited most of his appearance from his father, it seems, due to his physical appearance and his Z-Staff. 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 (similar to Grimlord from VR Troopers) face, 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.

He was imprisoned by the Sentinel Knight in a space dumpster, much like Zordon had done to his mother pre-Mighty Morphin Power Rangers. He grew stronger as the Sentinel Knight grew weaker and was able to escape as his mother did on the moon, and now he sought revenge on the Sentinel Knight. Angry at his parents for becoming good and wanting to restore their evil legacy, he united the four Overdrive villain groups into an alliance to destroy the Power Rangers. They managed to defeat the Rangers easily and break their link to the Universal Morphing Grid, stripping them of their powers.

When the Sentinel Knight responded by creating a team of veteran Rangers, Thrax decided to seek out the magical sword Excelsior to destroy him - following Mack right to it. However, because of Thrax's evil nature, he was unable to claim the sword and he retreated to continue his rampage. Thrax proved to be a strong fighter in the final battle, managing to overpower the Defender Vest, before being beaten aside by Adam. Thrax was finally destroyed by the newly (and fully) restored Sentinel Knight, causing the other villains to retreat and continue their rivalry.