Isogin Jaguar (イソギンジャガー Isoginjagā) is a sea anemone/jaguar monster originally known as Yosuke Katsurajo (桂木良助 Katsurajō Yosuke) who turned into Gel-Shocker kaijin by General Black. After defeated by Kamen Rider 1's Rider Point Kick and saw Katsurajou Maki calling him, he jumps then reverts to human form and still remember his beloved daughter.
Isoginjaguar was voiced by Mahito Tsujimura (辻村 真人 Tsujimura Mahito). Katsurajou Yosuke was portrayed by Shin Ogami (大神信 Ogami Shin).
Super Hero Taisen
Another Isogin Jaguar was created as part of Dai-Shocker in the "super hero taisen" incident, led by Tsukasa Kadoya/Kamen Rider Decade, rivaling Captain Marvelous/Gokai Red and Dai-Zangyack. However, Rider Hunter Silva of Dai-Zangyack and Doktor G of Dai-Shocker overthrew their respective leaders and joined forces to destroy the Kamen Riders and Super Sentai. The two evil organizations united and faced off against the combined forces of the Sentai and Riders. He is seen fighting MegaBlack, Kamen Rider RX, ShishiRanger, Battle France, Kamen Riderer ZO, and TimeGreen. During the final battle, Isoginjaguar was killed by Kamen Rider OOO's finishing attack with his Medajalibur, the OOO Bash along with Hades God Dagon, Scorpion Man, and Ghoster.