Rigel

Rigel is a planet of advanced technology, home to the greatest technological minds of the universe. This planet of geniuses manipulate "Triangle Power" to run and control their systems, which can only be utilized by they alone. Their genius is so great that even a young child from this planet can possess a mind that is smarter than an entire space force.

Seeing the genius of the Rigelians and wishing to use it for their own, General Giluke chose to place a plan in motion to manipulate one of these genius children to assist their forces. His forces end up taking a young girl named Nana without telling her she has left the world, creating the illusion that she was still on her homeworld while killing her father and replacing him with Dr. Kumazawa, an Earthling lookalike who wished to betray Earth to gain intergalactic power. Without telling her the truth, Nana assisted them in a project to empower Gyodai with energy to grow creatures on a massive scale without tiring as typical whenever the Gyodaian used his growth beam. However, the intervention of Hiryuu Tsurugi made Nana realize she was no longer on her homeworld, yet with her staying on Earth instead even after the betrayal to find further information about this backward world.