ゲートキーパーズ21

"Gate Keepers 21" (ゲートキーパーズ21) is a six-part OVA sequel to the anime series "Gate Keepers," set 31 years after the TV anime, presenting a darker and more serious plot. It resolves some of the questions left unanswered in the original series. Key elements linking the two include Reiji Kageyama, Yukino Houjo, and Tategami High School, the former headquarters of the Far Eastern AEGIS branch. Set against a backdrop of a declining Japan after the Shōwa period, the series portrays a society marred by economic stagnation, increased crime, environmental issues, and international instability. A new type of Invader emerges, no longer an alien entity but capable of absorbing ordinary humans. The remnants of the disbanded AEGIS have formed a clandestine network to fight the Invaders, led by the antisocial Ayane Isuzu. She collects Invader crystals in exchange for money from the mysterious Reiji Kageyama. The series explores themes of human selfishness and apathy, raising the question of whether the "Invaders" are hidden enemies or a manifestation of abhorrent human behavior.