Malekith is the first book in The Sundering series by Gav Thorpe. The book covers large swathes of history dealing with the events leading up to the Sundering, the civil war that split the the peoples of Ulthuan into the Dark and High Elf factions.
Passed over to succeed as king, elf general Malekith is wracked by jealousy and bitterness. Under the pretence of rooting out the pernicious cult of pleasure that is corrupting elf society from within, Malekith plots his revenge. When he betrays Phoenix King Bel-Shanaar and attempts to seize power for himself, Malekith triggers a tragic sequence of events that plunges the realm of the elves into a civil war from which they will never recover.
Malekith's story is broken into two main acts.
The first act spans a thousand years and describes how Malekith was passed over to become the Phoenix King and his subsequent conquests outside of Ulthuan. Malekith's bitterness grows as he works to expand Ulthuan's power and colonize the known world, but is slighted at every turn by Ulthuan's politics. Malekith eventually meets and befriends the Dwarfs, forging an alliance to clear the Old World of Orcs and Chaos Worshippers. Eventually Malekith and his army venture into the Chaos Wastes where he discovers the Iron Circlet.
The second act spans far less time and covers the quelling of pleasure cults in Ulthuan. The story begins from Carathril's point of view, a high elf soldier. Armies from the south travel north to destroy cults that have infested society. Eventually Malekith returns to Ulthuan with his army and helps the battle, leading to the story's climax.