Synopsis
Gaira, a humanoid sea beast spawned from the discarded cells of Frankenstein's monster, attacks the shores of Tokyo. While the Japanese military prepares to take action, Gaira's Gargantua brother, Sanda, descends from the mountains to defend his kin. A battle between good and evil ensues, leaving brothers divided and a city in ruins.
Cast

Kenji Sahara
Dr. Yuzo Mamiya

Kumi Mizuno
Akemi Togawa

Russ Tamblyn
Dr. Paul Stewart

Jun Tazaki
General Hashimoto

Kipp Hamilton
Singer

Yoshibumi Tajima
Officer Hirai

Nobuo Nakamura
Professor Kita

Hisaya Ito
Chief Izumida

Nadao Kirino
Lt. Col. Kazama

Ren Yamamoto
Saburo Kameda

Kōzō Nomura
General's Aide

Shōichi Hirose
Soldier

Tadashi Okabe
Defiant Reporter

Hideo Shibuya
Skeptical Reporter

Ikio Sawamura
Fisherman #1
Seishirō Kuno
Fisherman #2
Someshō Matsumoto
Official

Gorō Mutsumi
Dr. Paul Stewart (voice)

Haruo Nakajima
Gaira
Hiroshi Sekita
Sanda
Yasuhiro Komiya
Adolescent Sanda
Kasei Kinoshita
Adolescent Sanda (voice)

Yū Fujiki
(uncredited)
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