Sengoku Monster Chronicle Raigora

Motonari Mori vs. Harukata Sue! It's the Sengoku period. Jurota, a man who dreams of rising through the ranks with the sword, takes part in the Battle of Itsukushima as part of Harukata Sue's army. Just as the surprise attack against Motonari Mori is about to be decided, the sea splits open and a giant, mysterious creature appears.