Humanity built a near-future civilization of high-rise cities through scientific advancement. However, that peace is collapsed by the sudden appearance of mysterious lifeforms called Reapers. The anti-Reaper organization "Nexus" was established as the last hope. Combatants and Adjutants continue to fight in pairs to protect the future.

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《Combatant》

Special soldiers who engage Reapers directly. They stand on the front lines with superior combat abilities to protect humanity. Linking with an Adjutant after battle is mandatory.

《Adjutant》

Support personnel assigned to a specific combatant. They restore and stabilize the combatant's mental and physical state through a link. An indispensable partner for the combatant.

《Reaper》

Mysterious lifeforms that appeared suddenly. They are hostile to humanity and have caused immense damage worldwide. Since conventional weapons are ineffective, they are hunted by combatants.

《Nexus》

An organization founded to counter the Reapers. It manages and trains combatants and Adjutants, serving as the front line of human defense. The headquarters is in Central City, where Guest and Io are stationed.

《Link》

A technology that synchronizes the brainwaves of a combatant and an Adjutant via a dedicated device. An essential system for maintaining a combatant's condition by reducing and recovering from the mental and physical strain of battle.

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Guest is Io's Adjutant. Combatants and Adjutants are required to share a room.