The slow and less-intelligent Whale Imagin wields a staff with a fluke at one end and has the ability to breathe water from its mouth. When Kōsaku Higuchi wishes to get rid of his drinking problem, the Whale Imagin fulfills this wish by attacking anyone who knew of his drinking problem: former employees and a sake vendor. Once in the past, he attacks people who were having a hanami party under a starlit night sky. The Whale Imagin is confronted by Den-O Sword Form and Gun Form, and is destroyed by Den-O Sword Form.
Whale Imagin revive with the massive army of Imagin that invaded both the past and the present as part of Kai's plan to ensure the Imagins' future, this armed with a sword rather than a staff.
Kamen Rider Decade
To be added