Malekith is the main antagonist of Thor: The Dark World.
Thor: The Dark World
He is the leader of the Dark Elves who seeks to plunge the nine realms into darkness using his weapon the Aether.
Malekith is first seen battling Odin's father Bor and his Asgardian forces when he attempts to unleash the Aether. Bor is victorious, which forces Malekith and his Dark Elves to retreat into suspended animation, until the Aether is found and bonded with a host.
Thousands of years later Human scientist Jane Foster accidentally stumbles on the Aether and becomes bonded with it, this awakens Malekith and his army, sensing the Aether's power he hatches a plan to get his weapon back. After being infected by the Aether Foster is transported to Asgard by Thor for treatment, sensing this Malekith gives his liutenant, Algrim, a Kursed stone and secretly plants him with prisoners being transported to Asgard's holding cells. After Algrim uses the Kursed stone to turn into the powerful warrior "Kurse", he breaks free of his cell and manually drops Asgard's defenses letting Malekith and his army invade unhindered.
Once within the halls of Odin's kingdom, Malekith and Kurse seek out Foster, however Frigga, Thor's mother, defends Jane and briefly fights Malekith resulting in her death at the hands of Kurse. An enraged Thor attacks the pair of Dark Elves, gravely wounding Malekith before they are both able to escape back to their home realm Svartalfheim, where Malekith is placed in a healing chamber. Eventually Thor and Loki, with Jane, track down Malekith to Svartalfheim once they arrive Malekith is able to sense the Aether within Jane and leaves his ship to meet Thor. After Loki seemingly betrays his brother and hands over Jane, Malekith proceeds to extract the Aether from Jane, Thor and Loki quickly reveal the betrayal was only a ruse and attempt to destroy the dark weapon with Thor's hammer. The Aether however quickly reassembles itself and it is subsequently ingested by Malekith himself, he then leaves for London, to complete his plans to bring darkness to the realms while Kurse stays behind to battle Thor and Loki, but is killed, seemingly at the cost of Loki's life.
Malekith arrives in London and is greeted by Thor the two then duel, with Malekith using the power of the Aether and Thor using Mjolnir, with both being an even match for the other. Eventually a portal seperates the two during battle leaving Malekith on Earth and Thor in the Elf realm. Malekith, unaposed begins to unlash the Aether's full power, however Thor is able to come back using another portal, and a Tube train, in time to stop him.
During their final battle Thor uses Eric Selvig's portal devices to impale Malekith through the chest, which after activating sends him back to Svartalfheim. The Aether shuts down, and Malekith's ship begins to crumble and fall into the London streets on Thor and Jane, only for Selvig to use another one of his portal devices to send the falling ship into Svartalfheim and crashing into a wounded Malekith, finally killing the Dark Elf for good.
◾In Hulk and The Agents of S.M.A.S.H Malekith has the same outfit as his Marvel Cinematic Universe Incarnation except that his skin is the same as his Comic Incarnation and the right half of his face is fully black. ◾Despite being classified as a Dark Elf, Malikith has brighter beige skin rather than Blue, Brown, Purple or Onyx though eventually his skin became the later after acquiring the Aether resembling one of the classic dark elf depictions.