Sea of Crimson Mist, a Fallen Zone marked by the Star Envoy Association.
In the Star Envoy Association's regional classifications, areas were divided into five levels: Safe Zones, Low-Risk Zones, High-Risk Zones, Fallen Zones, and Forbidden Lands.
Safe Zones were places like Deep Blue City and Steam Capital, protected by Calamity-class Star Beast Mimic Obelisks—Star Monuments for short.
They were areas where even ordinary people could move about freely, with only an extremely small chance of a "Star Beast invasion."
Low-Risk Zones referred to areas inhabited only by Level 0 to Level 1 Star Beasts. As long as ordinary people were careful, they could enter and explore them.
High-Risk Zones referred to areas inhabited by Level 1 to Level 2 Star Beasts, with a small chance of Level 3 Star Beasts. Non-Star Envoys were forbidden from entering; they were exceedingly dangerous.
Fallen Zones and Forbidden Lands, meanwhile, were somewhat special.
Judging by the observed energy levels of the Star Beasts, the two were roughly the same, both containing Level 3 and above, or even higher-level Star Beasts.
Thus, the only standard distinguishing them was whether Association Star Envoys who entered to explore could come out alive.
If Association Star Envoys above Level 3 had entered to explore and successfully emerged, such an area would be called a "Fallen Zone."
If Association Star Envoys above Level 3 had entered to explore, yet not a single one had made it out alive,
then such an area would be called a "Forbidden Land," a place even Calamity-class powerhouses did not dare set foot in lightly.
The area the Steam Train was currently traveling through was the boundary between a Fallen Zone and a High-Risk Zone within the Sea of Crimson Mist.
The reason this location had been chosen was because of the Sea