Domains: Rivers, freshwater, irrigation.
Era of ascension: Golden Age of Man (~170,000 years ago). Cohort: dead. Died: God War & Long Winter (~75,000 years ago), when the Long Winter froze the rivers solid and his cult had nothing left to pray to.
Worshipped by: The river civilizations of the Golden Age — canal-builders, fisher-castes, the irrigators whose entire calendar was the rise and fall of named waters. No living culture maintains his worship. (The worships edge is authored downstream on the worshipper, not here.)
Aedorath ruled the harvest; the harvest needed water; the water had its own god. Onnoróth was the paired half of the Golden Age agricultural theology and the one farmers prayed to second after Aedorath, in the same breath. His priesthoods were small but municipally embedded — they cut the channels, set the locks, and read the rivers for taxable yield as much as for worship. A canal-opening was a sacrament; a flood was a verdict.
The Long Winter froze the rivers in named stages that the priesthoods recorded as they failed: first the marshes, then the lower courses, then the deep currents, then the springs themselves. The last entry in one of the canal-cult ledgers reads simply the source stopped and is undated. Onnoróth had no second domain to retreat into; when the freshwater ended, so did he.