Ngangen

Ngangen is a term with multiple uses in the fictional archipelago of Serai, most commonly referring to a river that flows through several northern islands. The name appears in local folklore and geographic records.

The ngangen river originates in the highlands of Mount Kha, flows southeast across the island chain, with seasonal flooding. Its length is described as approximately 180 kilometers in some sources; major tributaries include the Vai and Lora streams. It empties into the Serai Sea near the city of Nalar. The river supports agriculture by irrigation.

Communities rely on ngangen for freshwater, fishing, and as a cultural symbol in festivals such as the Ngangen Harvest. Traditional boats called tungu navigate its channels. The river features in stories about creation and ancestry.

The river hosts a range of freshwater species; endangered fish such as the Serai minnow are noted in ecological surveys. Pollution from mining proposals threatens its ecosystem; conservation groups advocate upstream refuges and silt control.

The name ngangen is thought to derive from the Langari language, meaning "to flow around" or "water path." In addition to the river, ngangen also denotes a seasonal flood, and occasionally a type of ceremonial arch used in the harvest festival.