Iron Ring Mask is a Black Cross Army Masked Monster made up of stacked metal hoops.
Iron Ring Mask led an operation in gaining secret access to an EAGLE base containing a microfilm that includes many EAGLE secrets, including base locations, projects and all known information about the Gorenger. Kaijo and Asuka pursue him, but he takes a houseboat hostage to save his life, while hiding from the two Gorenger by splitting into his iron rings and blending in.
After the Gorenger leave, Iron Ring Mask uses the telegraph on the boat to start reporting secrets to the Black Cross Fuhrer, leading to the destruction of multiple EAGLE bases, though the Fuhrer tells him to get the Gorenger secrets. Kaijo and Asuka return to the boat after witnessing the Black Cross' destruction and find Iron Ring Mask, while the other Gorenger catch up using Variblune. Iron Ring Mask tries to use a motorboat to escape, but the Gorenger hit him with Gorenger Storm from a distance, making both him and his escape boat explode.
Modus and Arsenal
He can split his body into multiple rings which allow him to sneak into places and restacks them in order to utilize a humanoid form; he also can use his rings as weapons and has super strength. His most dangerous attribute, though, is a computer installed within his body that can analyse information, including through microfilm cassettes it can install into its head, that can steal enemy secrets.