Dethorin

Dethorin was the original wielder of the Killmaim, after it appeared out of the ground in response to his cries. With it, he killed his lady Allurana and her lover for whom had been the cause of his woe and the Killmaim's appearance. After killing the two, he disposed of the Killmaim by throwing it in the ocean.

Speculation
It is presumed, although not certain, that both Allurana and Dethorin were night elves.