The Sundering (Warhammer Chronicles)

Malekith, betrayer and usurper, architect of the great war that will forever divide the race of elves. Alith Anar, wrathful avenger whose spirit will forever haunt the traitorous druchii. Caledor, reluctant leader, the one elf who can hold back the darkness and restore peace to Ulthuan. Witch King, Shadow King and Phoenix King. Their deeds are legend. This is their story.

Three books by Gav Thorpe -
Malekith, Shadow King and Caledor,
plus two short stories tells recalls the story of the Sundering of the Elves.  Tempted by power Malekith succumbs to the dark power and brings the elves to civil war