Ranger Reject, 1

A ship in the form of a floating castle suddenly appears more than ten thousand meters high. Everything indicates that it is a villainous alien troop with supernatural powers whose purpose is to invade Earth and dominate the entire galaxy. Luckily the fate of humanity rests in the hands of the Divine Dragon Patrol, a superhero squad that will take down evil! Or, at least, that's what they want everyone to believe... The truth is that the aliens are subjugated by the Dragon Keepers and are nothing more than fairground monkeys forced to produce piecework monsters for the pure entertainment of the masses. However, everything changes when one of the aliens decides to take action on the matter and infiltrates the patrol entrance exam to eliminate them one by one from within...