Domains: Music, song, oral memory.
Era of ascension: Golden Age of Man (~165,000 years ago). Cohort: dead. Died: God War & Long Winter (~75,000 years ago), when the Winter silenced the singers before they could teach the next generation and the chains of memory she required snapped at every link at once.
Worshipped by: Bardic schools of the Golden Age, court musicians, and the song-keepers attached to the great households — those whose office was to know the songs by heart and to teach the apprentice who would replace them. No living culture maintains her worship. (The worships edge is authored downstream on the worshipper, not here.)
Worship of Hellúneth took the form of performance, and performance was the worship. Where Graelith presided over written knowledge — the scroll, the wax tablet, the library — Hellúneth was the deliberately oral counterpart, sung out at every hearing and unfixed by ink. The bardic schools justified the choice theologically: a song that was written was a song that had been taken from the goddess and kept; a song that was sung was a song given back. Her cult therefore left almost nothing the libraries could have preserved.
The Long Winter cut the chain in the simplest possible way. Apprentices died before their masters could finish them; masters died before their apprentices could learn the closing verses; the last song-keepers held what they remembered in private and then froze, and what they remembered froze with them. Her death is the structural reason that no Golden-Age song survives — even the surviving libraries, which kept what they could, kept no music, because Hellúneth's worship had insisted there was none to keep.
She is distinct from Graelith by medium and by intent: Graelith fixed knowledge so it would last; Hellúneth refused to. The Winter punished the refusal absolutely.