Lake Mobius (湖メビウス) is a massive lake in the center of the Dark Continent. It is conventionally divided in three sections: Human Territorial Waters, which encompass the relatively diminutive territory occupied by mankind, Untamed Waters, where the New Continent is located, and Dark Waters. The latter two are divided by the Border Waters, an area where passage is regulated by the Gatekeeper. However, the public at large is aware of a different partition, that of Territorial Waters and Uncharted Waters, which in reality accounts only for the two bodies of water before the Gatekeeper's territory.
- The shape of the lake is somewhat similar to a Möbius strip.