Doctor Shinigami

Doctor Shinigami is an executive member of Shocker from Switzerland. After Colonel Zol's destruction at the hands of Kamen Rider 2 Shinigami takes command of Japan's branch. When Takeshi Hongo appears to fight him Shinigami discards his cape and transforms into his Inhumanoid form, Ikadevil, a Squid Kaijin with the ability to use his tentacles as whips. Ikadevil had Shocker Soldiers take care of Ichimonji while he fought Hongo. At first Ikadevil had the upper hand, with guidance from Tobei, Rider 1 manages to overpower Ikadevil and weaken him with a Rider Chop before finishing him off with his Rider Tailspin Shoot.

Kamen Rider Decade
In Kamen Rider Decade: All Riders vs. Dai-Shocker, Ejiro Hikari is revealed to be a guise for Doctor Shinigami using cape once again to assume transformations. Like in Kamen Rider, Shinigami has the ability to assume his Inhumanoid form, Ikadevil. In the film Ikadevil now has the ability to shoot flamming squids at his opponents called Ika Missiles. He is destroyed in the final battle against the Riders by Kamen Rider Decade, Kamen Rider Diend, and Momotaros using the Final Form Rides of Kiva, Blade, and Faiz. Despite this Ejiro lives having no memories of being Shinigami.

In Kamen Rider Decade: Final Chapter, Ejiro regains his memories after seeing a squid dish presented to him by Narutaki. Through the Golden Shinigami Hakase Gaia Memory, given to him by Ryubee Sonozaki, Ejiro becomes Super Doctor Shinigami, the leader of Super Shocker. In the movie he revives the Neo Organism to destroy Decade. But when a revived Decade along with Diend, Kuuga, and Kamen Rider Kivala fight against Super Shocker, Super Shinigami in Super Crisis Fortress the Gaia Memory comes out of his neck and reverts back to Ejiro. He is saved by Kivala before the Fortress is destroyed.