A race of aliens that planned to eliminate Ultraman Jack for being an obstacle to their Earth invasion plans. Alien Nackle are cunning and coldblooded. They attack their enemies with mighty punches and kicks and by firing beams from their eyes.

Disguising themselves as scientists at the cosmic radio waves research facility, Alien Nackle revived the Tornado Monster Seagorath and the Great Space Monster Bemstar in order to analyze Jack’s fighting abilities. Next, using their Bodyguard Monster Black King as a decoy, Alien Nackle stole Saturn Z, a liquid explosive that MAT developed.

Even worse, Alien Nackle ran over Ken Sakata and his younger sister, Aki. It called on Black King again and Hidek Goi, consumed with grief and rage, transformed into Ultraman Jack. Alien Nackle revealed himself and turned into a giant. The alien teamed up with Black King to defeat Jack, and then carried him to Planet Nackle on their spacecraft.

Alien Nackle then tried to manipulate the MAT members and destroy the organization, but was stopped by Ultraman Jack after Ultraman and Ultraseven revived him. Alien Knackle and Black King fought with Jack again. At first it seemed they were winning, but Jack countered with his Ultra Throw technique and Alien Nackle was killed.