Reigo: The Deep-Sea Monster vs. the Battleship Yamato (深海獣レイゴー Shinkaijū Reigō) is a 2008 independent tokusatsu film by Shinpei Hayashiya. Veteran artist Keita Amemiya designed the titular monster. The film's original working title was Reigo vs. Yamato (レイゴー対大和 - Reigô tai Yamatô).
The film, set in World War II, depicts the story of the real-life Japanese battleship, the Yamato, which is confronted in the Pacific Ocean by giant monsters, including the most fearsome of them all, Reigo.
But to Osako’s annoyance, Momoka brings along her elderly grandfather (Mickey Curtis) who insists on telling him a local tale about monsters that has been passed down for generations. The disbelieving naval officer is told that the surrounding waters are home to man-sized, carnivorous Bonefishes…and, as dangerous as the fish are, they are nothing more than an “opening act” for an even greater menace; the legendary Hell King of the Seas called Reigo.
The next night, a lookout spots a massive shape half-submerged in the distance. Believing it to be an enemy submarine, the Yamato fires on it and scores a direct hit. Osako is shocked when the object emits a strange cry as it sinks beneath the waves. He reports the incident and the story of Reigo to his commander and shipmates. Unbeknownst to the crew, they have killed the offspring of Reigo.
Not long after that first encounter, a school of luminous Bonefish launch themselves from the water like flying fish and attack a group of soldiers standing watch on the Yamato’s deck. Kaido hears their screams and rushes to the rescue, but finds the men already torn to pieces.
Just as the old man predicted, the Bonefish herald the arrival of Reigo, a beast 80 meters-long and resembling a cross between Godzilla and a shark. Seething with rage at the murder of its cub, the monster attacks the Combined Fleet with incredible ferocity and awesome destructive power. The naval forces are caught off guard, and Reigo is able to destroy escort ships and damage the Yamato before returning to the ocean depths.
The crew quickly regroups and plans a counterattack, but when Reigo returns it manages to stay one step ahead of the Japanese forces. Almost as if it is aware that the Yamato’s main guns are long range weapons which are ineffective up close, the monster attacks at close range or blasts the ships from underwater with blue bursts of electricity.
Thoughts of family and lovers back home… fear at being confronted by an unknown enemy…conflict and confrontation explode among the officers and crew over the best battle strategy to use against the threat of Reigo.
Over Osako’s loud objections, Kaido suggests a last-ditch plan of attack that will either stop Reigo or sink the Yamato. Now the stage is set for a final battle to unfold between the world’s largest battleship and the mysterious dragon-like monster that glides through the seas at will.
Which one will prevail… Reigo or the battleship Yamato?
In 2009 director Hayashiya made a follow up entitled The Deep-Sea Monster Raiga (深海獣雷牙 Shinkai-jū raiba). The film features a more traditional Godzilla like kaiju called Raiga. The creature rises from the sea to do battle with another of his kind.