Nisien is a figure in Welsh mythology, the son of Penarddun and Euroswydd and twin brother of Efnysien.[1] He appears in the Second Branch of the Mabinogi, which names Brân the Blessed, Branwen, and Manawydan as his half-siblings. Nisien, also Nissyen, was the opposite of his brother Efnisien in personality. He was tranquil and generous, while Efnisien was vindictive and destructive.


  1. ^ Meulder, Marcel (2008-06-30). "Nisien et Efnisien: couple odinique ou dioscurique?". Nuntius Antiquus (in French). 1: 141–158. doi:10.17851/1983-3636.1..141-158. ISSN 1983-3636.