It sells you a bright fantasy party quest for one arc, then has Yuri, the man leading the Volunteer Army, turn his back on every person who followed him and walk into the Black Army's ranks. That betrayal is the show's whole spine, and everything after it is Aram and Phoena carrying a war they were never built to win, with Phoena's link to the Chain Chronicle turning her into both the map and the target. The setup does the unglamorous work most game adaptations skip: Yggd's kings squabbling, the chosen lord holding a fragile balance, and the exact moment that balance stops meaning anything. Graphinica's battle staging keeps the scale honest, big lines of soldiers instead of two people trading beams in a void. It comes from a Sega mobile game and still finds room for the specific hurt of following someone who stops deserving it.
A legendary book records everything that transpires across the world, but when the Black Army invades the isolated continent of Yggd, half of it falls into enemy hands. The delicate balance maintained by regional kingdoms shatters overnight as this conquering force sweeps across the land, leaving devastation in its wake. Yuri leads a hastily assembled Volunteer Army against overwhelming odds, but their initial resistance crumbles beneath the Black Army's relentless assault. With the capital occupied and the Chain Chronicle split between two powers, the fate of the entire world hangs in doubt. The remaining half of the book becomes humanity's only hope for understanding what comes next, yet knowledge alone may not be enough to turn the tide. Survivors must band together and venture into dangerous territories to rally allies and uncover the truth behind this invasion. Every battle matters when the very record of existence itself is at stake. This is a story of desperate people fighting to reclaim their world before the Black Army rewrites history itself.