Go! Go! Loser Ranger! (戦隊大失格)

Storyline

13 years ago, a giant floating fortress appeared 10 kilometers in the sky, and an evil army called "Kaijin" started attacking humanity. The Kaijin have regenerative powers, so they are effectively immortal and pose a real threat to humanity. A new organization called Ryûjin Sentai Dragon Keeper featuring people with mysterious powers and weapons called Jingu continue to fight against the Kaijin to this very day.