|This article is about a/an monster in Power Rangers Operation Overdrive.|
This black-and-blue-colored keylock/laser disc-themed monster was first seen trying to "kidnap" Mira in order to lure Dax to where he was in the city. Dax attacked the monster and gave him a beating to impress Mira; soon the monster retreated. Later, Ultrog returned, seeking the Neptune scrolls. The Rangers battled him, but because Dax's heart was so tender after thinking about Mira, Dax could not handle him. Ultrog threatened to take Mira away again unless the Rangers gave him the scrolls. Dax, feeling helpless, handed them over, but the monster left with Mira anyway. Ultrog had absorbed the power of the two scrolls he had taken, making him stronger than before. He proved to be too much for the other four Rangers when he battled them again that night, but the tables were turned when Dax came back to join the others, as well as to reveal that the third scroll that Mira (who finally revealed to Dax her true identity of the evil Miratrix) had stolen was a fake. The Rangers soon took out Ultrog, but from inside the jewel of Miratrix's necklace, Kamdor used a sutra to make Ultrog grow. After forming the DriveMax Megazord, Ultrog had the upper hand again, but then Spencer gave the Rangers the power of the third scroll, which allowed them to suck the power of the other scrolls out of the monster; the scrolls then made their way back into Spencer's hands. Soon afterwards, Ultrog was destroyed by the DriveMax Megazord Saber.
- Ultrog resembles the Storm Megazord of Power Rangers Ninja Storm, the reason for this is because Ultrog's Boukenger counterpart, Jougami, as with each primary antagonist and each individual monster of the week was visually designed as an homage to the various robots and other mecha piloted by the protagonists of the 29 previous Super Sentai Series (except for J.A.K.Q. Dengekitai), as Boukenger was the 30th anniversary series. Nendogami's look was based on the Storm Megazord's counterpart, the Karakuri Giant Senpuujin of Ninpu Sentai Hurricaneger.