The Halanan wife of Professor Gideon Seyetik, whose unhappiness in her marriage unconsciously creates a psychoprojective double named Fenna, with whom Benjamin Sisko falls in love in 2370.
Nidell is a Halanan woman who appears in the second-season Deep Space Nine episode Second Sight. She travels aboard the USS Prometheus with her husband, the celebrated and overbearing terraformer Gideon Seyetik, who is about to reignite a dead star.
Halanans mate for life, and Nidell cannot leave him. Under deep emotional strain her people can project a living image of themselves, and without knowing it she sends out Fenna, a free-spirited woman who meets Sisko on the Promenade. Each projection drains her and she begins to die.
Seyetik, understanding at last, pilots the shuttle into the star himself. His death frees Nidell, who recovers with no memory of Fenna or of Sisko.