Her father is either Mend[3] of Inis Fer Falga (identified as the Isle of Man), Iuchna,[4] Conchobar mac Nessa,[5] or Midir, the fairy king of Brí Léith (from Westmeath).
[6] Later, she betrayed her husband to his enemies, pouring milk into the River Finglas (Finnglas), supposedly at the Caherconree Fort, as a signal he was at home.
Bláthnat's floral name and the story of her conspiracy have been compared to those of Blodeuwedd in the Fourth Branch of the Mabinogi, Math fab Mathonwy.
[7] Blathnat makes an appearance in the Fled Bricrenn (Feast of Bricriu) as the wife of the absent Cú Roí.
She tells each of the three heroes to guard the fort on different nights, however only Cú Chulainn is able to defeat the force.