Door Mask was in charge of the abduction of EAGLE's new Super X computer, stolen from a base and placed within a train to transport to the Black Cross for a plot to use it to align their satellites to drop bombs for destroying Tokyo. When he initially faces the Gorenger, he uses misdirection to trap four members into a box with a bomb lock holding them; however three of them escape using Kirenger's strength and his Birdies, while Akarenger digs underground using his Red Bute Drill to escape. Eventually, Kaijo catches up with the train with the help of the computer and tries to retrieve the Super X computer from Door Mask, but the computer explodes before he can save it, appearing to destroy itself to protect its secrets.
When Temujin catches up with them, he reveals the core computer of Super X still existed, which he placed inside Door Mask to continue with the Black Cross's plot. Temujin prepared to execute Kaijo by having a train run over him, but Akarenger decides to save his life by claiming to tell them the secrets they require, only to use it to release a carrier pigeon to alert the other Gorenger of his whereabouts. When Door Mask continues to interrogate him, Kaijo uses magic of his own to spit out a stream of handerchiefs to tie him up. However, a bump on Door Mask's head ends up fusing Super X's programming with his own, merging the two together and increasing Door Mask's power a hundredfold. The Gorenger use a special Gorenger Double Storm to finally defeat the Masked Monster even at the loss of their former computer.
Modus and Arsenal
Door Mask's main ability is to set up locks on doors that are unbreakable and prevent escape; but generally only prevent escape from the portal it is locked with, not protecting any of the other portals within a room. He can also use bomb locks to blow up objects and has a key-based staff. Door Mask can also open the door within his head to collect and automate information within himself.
After he "merges" with Super X, Door Mask gains power 100 times greater than his own, but ends up losing his mind as Super X takes over and becomes merged with his own personality into a hybrid being.