In the year 2025, at the end of December, Crimson descended from the sky. The Tree of Life, Apostles, Mobile Iron Cavalries: when Crimson descends, when the world changes drastically, when civilization shatters, there is always a need for a group of people to step from the light into the shadows, pilot sacred iron cavalries, and stand before tens of millions of people. "Captain, the Monarch has descended." "Then set off, and nail it before the fortress." The magnificent purple pupils of the mobile armor lit up.