The Symbiotic Legions, invaders from the outer galaxy, who's goal to turn Earth into a planet they could live on. When they first came to Earth, They were very hostile creatures who attacked and killed many civilians on a train taking a seed that they would use to to spread their species across the world. However, Gamera sensed their presence and engaged them in battle, destroying the seed.
Eventually, the Queen Legion emerged to create another of her species reproductive flowers. She traveled to Sendai to unleash their pod. However, Gamera appeared and engaged the Queen in battle, but Legion brutally injured him and left.
She then went to Mt Akayuka, to make a final flower. the Army engaged her in battle to kill her, but she eradicated most of the military forces. Gamera appeared and the Legion Queen sent swarms of Legion Soldiers to kill him, but an air strike was sent and killed all of them, leaving the Queen Legion on her own.
Gamera and Legion engaged in battle. Air Support was sent to render some of Legion's arms. Gamera tore off her nasal horn, stunning Legion. Legion then tried to kill Gamera with her Energy whips. Gamera was forced to absorb some of Legion's mana, giving Gamera more power. Gamera then killed Legion with a beam of mana energy.