Sevenger is a Capsule Kaiju who first appeared in Ultraman Leo, as the fourth official member of Ultraseven's set of Capsule Monsters. After a long absence, a second Sevenger appears in Ultraman Z, this time as a human-built machine and part of STORAGE's arsenal.

One of the most powerful Capsule Monsters to be created from the Land of Light, Sevenger was encased inside a capsule-like object and was on his way to Earth, being transported by Ultraman Jack to Dan Moroboshi, as Dan couldn't transform due to his Ultra Eye being broken. Unfortunately, Jack was ambushed by the space monster Ashuran, and Sevenger was lost on Earth during the battle.

Sevenger was the very first anti-monster robot built for use by STORAGE, and is also used for disaster-relief missions such as removing rubble. When fighting, Sevenger's neutral eye expression changes to become serious. Its pilots are Haruki Natsukawa and Yoko Nakashima on a rotation shift. Sevenger's first fight was against a Namegon, after GAF America failed to capture, leaving it unchecked for two weeks. Sevenger's success convinced GAFJ that robots were a viable option as anti-monster weapons.