The Gate

Origin of the border

The Gate is the interdimensional portal that appeared in the Eterna Mountains within the former Kingdom of Lindsey. Demons emerged from it, and its arrival began the conflict later called the Demon War. No account in Volume I answers who created it or for what purpose; its importance lies in the war it made unavoidable and the settlement built around it.

Treaty and guardianship

The Treaty of Hope assigns the human-side Eterna range to demon territory and requires a fortress and guardian at the portal. the Tower was therefore established above the Gate, and its lord is bound to keep anyone from passing without permission while remaining neutral in human politics. That duty is the legal and moral frame for every later controversy around the Tower.

Political consequences

When Lindsey attempted to take the mountain range back, its army did not merely threaten a fortress; it challenged the postwar order centred on the Gate. The resulting First Transgression ended with Victor’s death and Lindsey’s dissolution. The portal is distant from the School’s arena, yet it shapes the history, fear, and authority that follow Ryuji into Volume I.

The portal beneath the Tower

Chapter 20 described a working emerald portal in a chamber deep beneath the Tower. Chapter 21 connects it to the Gate's function. When Shun Sato surrenders there, he orders Roku to guard “this gate” and let no one through, humans and demons alike — the Tower's treaty duty restated as a direct command. The portal's far side opens onto the Frontier, the capital of the Demon Continent, and it is the route by which the Royal Knights arrive and by which Shun is taken away.