Cú Chulainn
Cú Chulainn has many lovers, but Emer's only jealousy comes when he falls in love with Fand, wife of Manannán mac Lir. Manannán has left her and she has been attacked by three Fomorians who want to control the Irish Sea. Cú Chulainn agrees to help defend her as long as she marries him. She agrees reluctantly, but they fall in love when they meet. Manannán knows their relationship is doomed because Cú Chulainn is mortal and Fand is a fairy; Cú Chulainn's presence would destroy the fairies. Emer, meanwhile, tries to kill her rival, but when she sees the strength of Fand's love for Cú Chulainn she decides to give him up to her. Fand, touched by Emer's magnanimity, decides to return to her own husband. Manannán shakes his cloak between Cú Chulainn and Fand, ensuring the two will never meet again, and Cú Chulainn and Emer drink a potion to wipe the whole affair from their memories.