The Shadow Mamonos, now allied with Decay's faction, continue to operate in secret across the world.
In response, leaders from multiple nations have begun working together, but the true purpose behind the enemy's actions remains unknown.
What little is known points to a mysterious figure known only as "Lord", who issues orders to the Shadow Mamonos.
Among their ranks is a high-ranking member, the shadow of Atlante, who has begun creating Mamono clones from the shadows of the explorers themselves.
Unlike previous threats, these new creations flee immediately without attacking, suggesting they serve a far more specific goal.
It is also revealed that Atlante has produced shadow clones from Als and his siblings as well.

In hopes of unraveling the mystery, Minister Anth of the Republic sends the explorers to the Duchy to investigate the connection between the king of old and the lost Shadow Mamono techniques.
However, their research yields few results. Nagi then suggests they examine two places tied to the ancient kingdom: the ruins of the royal palace and the king's tomb.
Unfortunately, the tomb, located deep within the Permafrost, remains sealed off during the frozen season, making access impossible for the time being.
Instead, the explorers head to the Fountain of Recovery to speak with Izumi, the Water Spirit who now resides there, hoping she may have some insight.
Through this encounter, a new piece of the puzzle is revealed: Atlante's true objective and the hidden desire driving Decay.

Ahead lies a new truth, and deeper mysteries yet to be uncovered...