Eons ago, a man known as Eric Willis stole the Casket of Ancient Winters from Malekith, King of the Dark Elves, after discovering the dangers it held. Because he no longer possessed the artifact, Malekith could not properly hide from Odin, which resulted in the Dark Elf's banishment. He spent untold eons in limbo until Surtur arranged for his escape. During Malekith's stay in the nothing-dimension, Willis lived a long life on Earth keeping the Cask safe, but eventually had to pass the responsibility on to his son, Roger when Malekith tracked him down.
Malekith's reappearance came about during a time when Balder the Brave had vowed to put his sword down forever. So, when Odin asked that he of all Asgardians deliver a message to Loki, the mission took on a new level of seriousness.
When Balder finally entered Loki's chambers, the trickster revealed that he'd already been visited by another, Malekith, who he described as, "He whom Odin did banish to the limbo of endless night so many ages agone." Balder recognized the Dark Elf as a threat, but could not convey Odin's message before Loki had him bound and gagged.
Pushed to the absolute brink by his knowledge that the message he needed to deliver could save untold lives, Balder picked a sword back up once again and felled Malekith's troll minions. Upon regaining his audience with Loki and the Dark Elf, the brave one slashed at the denizen of Svartalfheim only to see him disappear before his very eyes!
Able to, at last, deliver the note to Loki, Balder's heart sank and his ire raised as Odin's step-son glibly tossed the letter aside and told him he'd already decided to join forces with Malekith. For his part, the Dark Elf used his teleportation abilities to make his way to Earth in an effort to uncover the Casket of Ancient Winters from Eric Willis.
To speed up the regaining of his prized possession, Malekith not only bent humans to his will with fruits of the faerie realm, but also ordered The Wild Hunt, a legion of supernatural dog-wolves. They brought him to Roger and the Cask, but also drew the attention of Thor!
Malekith almost had his quarry, but Thor remembered his weakness for iron. Though the Dark Elf fled, he didn't go far, appearing at the home of Melodi Thor's girlfriend who was actually Lorelei, the Enchantress' sister. There he added another spell to the mead she used to keep Thor in love with her, replaced Melodi with a stand-in and left a message for Thor: go to The Cotswolds of England with the Cask to get her back.
Having seemingly bested both Thor and Roger, Malekith attempted to open the Casket on an unsuspecting world, but Roger fired off one shot at the Dark Elf, hitting him in the arm and breaking his concentration. Thor soon returned to the battle field and tussled with Malekith who used his own shape-shifting abilities to fortify his physical form.
Though Thor had beaten the Dark Elf soundly, Malekith still rose once more and managed to shatter the Casket of Ancient Winters, unleashing blizzards of unknown proportions all across the globe. The act also allowed for Surtur himself to smash through his own prison and begin making his way towards the twilight of the gods. Thor then returned to Asgard with the unconscious Malekith over his shoulder, but still had to contend with the enraged fire god.
Later on, Malekith's machinations came to light when the creature known as Kurse wreaked havoc on Midgard after being rejuvenated by The Beyonder for kicks. As Thor swept in to stop it, Kurse remembered his old life as Algrim the Strong, a Dark Elf,who the Accursed one tasked with killing Thor by granting him the Kurse armor.
With some help from Beta Ray Bill and The Power Pack, Thor felled Kurse. Thanks to some quick thinking on Thor's part, The Beyonder sent the addled creature to Hel where he could seek out Malekith.
The Dark Elf appeared in shadow not long after as a guest in Loki's tower on the outskirts of Asgard as the Trickster plotted his takeover of Odin's land. Malekith's presence garnered the attention of Kurse after Hela managed to kick the thing out of her domain.
Before the confrontation, though, Malekith tricked Loki's ladyfriend Lorelei into drugging Odin's stepson as well as herself. Showing his own deceptive nature, Malekith cast a spell to make Loki look like the Dark Elf. He then sent Loki-as-Malekith out on a mission that was quickly stopped by Asgardian guards, leading to imprisonment. Meanwhile, the actual Malekith took the form of Balder who was supposed to take over as the new lord of Asgard. When Kurse attacked the real Loki, he directed Kurse towards the false Balder. The whole plan backfired on The Accursed as Kurse killed him in the form of Balder, which was soon discovered by Thor and the others.
Malekith and Lorelei teamed up once again down the line in Hel. He pushed her to appear before Ben Grimm using her magical wiles to get him to find a love potion she'd left behind on Earth. With The Thing under a spell, Malekith broke in and had him drink the potion himself, thus putting one of the strongest beings on the planet under the Dark Elf's control leading to a titanic tussle with Thor.
When that plan failed, Malekith looked for another even more powerful being to send after the Odinson and quickly turned towards manipulating Kurse who had become an official Asgardian and roommate of Heimdall. Kurse then forced his way down into Hel to confront Malekith. This time posing as Lorelei, Malekith tricked Kurse into heading to Earth and hopped a ride with him.
Thanks to one more bit of trickery, the Accursed cast another spell that made Thor appear as Malekith to Kurse. Kurse even went so far as to recruit the Midgard Serpent and the Ravagers from the Realms of Death and Ice to take out his enemy. An epic battle broke out as The High Evolutionary, the Godpack, The Warriors Three, Heimdall and Beta Ray Bill showed up to help Thor and Sif fight the mythical monsters.
Secretly, Malekith took over Jane Foster's form and used it to trick Sif into bringing Hela into the fracas. The goddess of death cleared Kurse's vision, showing Thor's true identity, but then made a deal with Thor. She would take the Ravagers back to Hel with her if the Odinson would go with her and become her dedicated warrior.
Back on Earth, the Godpack realized Malekith's Foster ruse and outed him. Though the Dark Elf tried to escape, the enraged Kurse tracked him down and would have killed him had Sif and the Godpack not interceded. Sif implored that they trade Malekith to Hela for Thor, a gambit that paid off.
During the time when Thor had been supposedly killed by Onslaught and sent to another universe, Malekith tried taking over Asgard, but got stopped by the combined efforts of the Asgardian warriors, Cable and X-Force. He also appeared on Earth as Malcolm Keith in service of a mysterious but powerful force in exchange for eventual control of Avalon. However, he made a fierce enemy when he manipulated the dragon Drake who fried the Dark Elf out of spite.
The villain made a true return after Thor himself came back to his home reality. At that point, Odin had faced the Dark Gods and brought back all of their prisoners, even their longtime enemies, including the Dark Elf, as a way to restore order and balance. Revived, Malekith did not waste much time. He quickly killed Jagrfelm who had come to possess the Cask of Ancient Winters, taking it back for himself.
At that time Asgard's leader had fallen into the Odinsleep. Malekith took advantage of the timing used the box to call forth Pentigaar, a demon made of ice. He sent the warrior to Earth in search of Asgardian blood, specifically Thor's, but first it clashed with Balder and then accidentally brought a revitalized Beta Ray Bill forth from a cosmic egg.
Having failed in that pursuit, Malekith next sent the cold winds of Ancient Winters to plague Sif, who had take over for Odin during his time of rest. The cold quickly froze the Golden City with the hounds of the Wild Hunt attempting to pick off stragglers. Upon entering Odin's chambers, they all attacked. The Dark Elf even managed to place a pillow over the All-Father's mouth and was moments away from suffocating him when Thor, Beta Ray Bill and the Warriors Three appeared to stop him.
Between attacking Thor with the actual Casket and also bringing Kurse back into the mix, Malekith appeared close to an actual victory. In fact, the Ancient Winters spread not just across Asgard but down into Hel. Taking a page out of his enemy's playbook, Thor fooled Malekith into entering the Hall of Lost Souls while he himself sought the Gem of Infinite Suns from Odin's personal horde. The Odinson quickly used the artifact to destroy the increasingly powerful Pentigaar, break Malekith's hold on Kurse and return the cold to the Cask before sealing it with the hot stone and sending the whole package into another dimension. Sif then had the honor of knocking the villain into unconsciousness for his transgressions against her and the realm.
During a time when Thor had been banished by Odin, Malekith appeared to the Incredible Hercules and his father Zeus — then a mind-wiped boy — in the guise of Balder asking for help in taking on a new threat to Svartalfheim, Alflyse, Queen of the Dark Elves of the Eastern Spires. Told that the elves truly feared Thor, Malekith gave Herc a Thor-inspired new look and sent him and the lightning bearing lord of the Greek gods on their way.
Malekith set them into motion as a way to empty the throne which would lead to control of all the Nine Realms. While on the mission, Herc got along so well with the queen that they had a very exciting night. Things got crazier in the morning, though, when the hero learned that he and Alflyse were officially married and that her forces were planning on invading Midgard and then Asgard for his sake. Since the actual Asgardians wanted to stop the war, but keep the more manageable queen in power, they dressed Thor up like Hercules and the two wore each out in battle, exactly as Malekith planned. With them tired, he dropped Grendell into the mix. However, a quick bolt from Little Zeus quickly ruined those plans and sent Malekith to dream up new plans of conquest.