HAKAIDA - The Destroyer
From Jinzo Ningen Kikaida episodes 37-42
Kikaida's younger brother and greates enemy. Kikaida was hampered in fighting Hakaida by the knowledge that the brain of Doctor Komyoji, Kikaida and Hakaida's maker, was in Hakaida's head. To defeat Hakaida ment killing Dr Komyoji. "hakai" is Japanse for "to destroy".
For more information see Jinzo Ningen Kikaida - Hakaida
There was a second Hakaida, in Kikaidaa 01 the sequel to Jinzo Ningen Kikaidaa, this Hakaida had the evil Professor Gill's brain. This Hakaida was meaner than the original, but not as interesting because he had less of a personality.
