A humanoid species with empathic abilities, represented by the Federation mediator Ves Alkar, who kept his calm by psychically dumping his darker emotions into chosen women, with fatal results for them.
The Lumerians are known from the Next Generation episode Man of the People. In 2369 the Enterprise-D carries Ambassador Ves Alkar, a celebrated Lumerian negotiator, to mediate the war between Rekag and Seronia. He travels with Sev Maylor, a bitter old woman he introduces as his mother, who dies on the way.
Alkar asks Troi to join him in a Lumerian funeral meditation. It is really the means by which he links to a new receptacle: his negative feelings flow into her, leaving him serene at the conference table. Troi becomes aggressive and jealous and ages by decades within days. Maylor, it turns out, was neither old nor his mother.
Alkar insists the peace he achieves outweighs the lives he uses up. Crusher briefly lets Troi die to sever the bond, and when he tries to attach himself to another woman, the returning flood of emotion kills him. Troi is revived and restored.