Sea vrykul

Sea vrykul, better known as Kvaldir, or tuk-hariq (meaning "walkers of the fog" or "sons of the mist" in the tuskarr language) are fearsome seafaring vrykul raiders who roam the seas raiding ships and coastal settlements.

Ancient history
Long ago, tribes of vrykul were scattered across ancient northern Kalimdor. One tribe in particular struggled against a terrible malaise that ravaged its people.

Combatting this affliction, this "curse of flesh," all but consumed the tribe. After exhausting all natural attempts, the tribe sought the aid of its priestesses. These women plumbed the world of spirits for answers, but they found only a malevolent entity lying in wait.

Their ritual went horribly wrong, as the entity further corrupted those that sought freedom from their curse. These eternally vengeful beings would later be called the Kvaldir.

Wrath of the Lich King
The vrykul had a burial ground in Howling Fjord called Shield Hill, and at some point just prior to the Wrath of the Lich King, a band of pirates happened upon the graveyard and stole several artifacts from several graves - graves of very important vrykul that had perished years before. The angry spirits of the disturbed graves are left howling for vengeance. The theft is discovered by the tuskarr, who were unfortunate enough to have several hunters approach the area due to the strange activity of the restless spirits of the dead.

As for the pirates, they've been hiding out and dealing with troubles of their own, as the artifacts they've stolen have proven to be far more trouble than their apparent worth. According to "Silvermoon" Harry at Scalawag Point, everyone who has come into touch with these artifacts has ended up dead, missing or both. The Frozen Heart of Isuldof drove one of the pirates insane, and now "Mad" Jonah Sterling hides in a cavern near the pirate cove, having assigned a bear to guard the artifact. The Staff of Storm's Fury had much the same effect on a crew member named Abdul the Insane, who now holds the staff on a ship at Iskaal. The giant Sorlof is holding The Shield of the Aesirites, and the only way to retrieve it is to gain the trust of the now-undead crew of the Sister Mercy and help them defeat the giant. As for The Ancient Armor of the Kvaldir, the armor was to be brought to Scalawag Point when the ship was attacked by Forsaken. The Forsaken boarded the ship and killed everyone aboard, looting everything of value until a small army of undead Kvaldir appeared and murdered the Forsaken. The ghosts of Kvaldir quickly overran the ship and now guard the armor from further tampering.

All of these items can be retrieved, and the plan of the tuskarr was to simply return the artifacts to their proper resting places. After all, if the spirits were angry at the loss of the items, surely returning them would appease the ghosts and cease the attacks upon anyone who ventured to Shield Hill. But the results of their plan did not play out as expected as the offering came too late.

The theft triggered the reappearance of the Kvaldir along the coasts of Northrend, including those located in Borean Tundra. But the Kvaldir didn't start their vengeance with the tuskarr - they started with the naga, and the sheer scope of their planned revenge for the stolen goods was far larger than anyone could've imagined. A naga priestess in Riplash named Veehja tells that five hundred years ago Queen Azshara imprisoned a being named Leviroth in the waters below. Now the Kvaldir seek to undo our queen's work by sacrificing naga and later on tuskarr. The Kvaldir were trying to free the kraken and presumably use it on the naga of Riplash, or on the tuskarr of the coast, or possibly on any living things that happen to be standing in the way.

Far in the upper reaches of Northrend, north of the newly constructed Argent Tournament, lies the fishing village of Tualiq. This small tuskarr village was also attacked by the Kvaldir and was quickly overrun, the bodies of slain Tualiq villagers littering the icy beaches. Led by Drottinn Hrothgar, they recently took over a tuskarr village on an island off the northern coast of Icecrown and renamed it Hrothgar's Landing. It is now a mist-shrouded staging point from which they launch attacks against Silver Covenant and Sunreavers' ships in the waters between the island and Icecrown. The Kvaldir seem to have one motive in mind - to summon another kraken from the depths of the Northrend seas. Adventurers can kill the summoners that seek to use the kraken, and they can kill the kraken itself from above, riding hippogryphs and hurling spears at the attacking creature. Once again, the Kvaldir seem to be focused on using a kraken to obtain their vengeance.

The Cataclysm
The Kvaldir make an appearance in the Shimmering Expanse of Vashj'ir. They appear in a vision of the past. They were lead by a general known as Varkul the Unrelenting. and were fighting Queen Azshara's naga, who wanted the the city of Vashj'ir but mostly the Crucible of Nazsharin from them. Adventurers experience this battle in the perspective of naga battlemaidens. They witness and help summon Ozumat. However, the sunken city of Vash'jir is being overrun by Kvaldir, who seem intent on wiping the naga out entirely. During the battle, the Kvaldir managed to steal the artifact that was to be used for the summoning ritual of Ozumat. The naga battlemaiden has to retrieve the artifact so that Ozmat may be summoned and so the Kvaldir can be summarily wiped out. Some remnants of the kvaldir force can still be seen at Biel'aran Ridge.

Appearance
Very similar to standard vrykul, these creatures are covered in green scales, barnacles, and seaweed. The Kvaldir typically reside deep in the ocean, where their corporeal forms would be crushed if their mistweaving magics didn't hold off the ravages of the depths. Although they remain flesh and blood in life, their deaths result in a backlash of mistweaving energies, dissolving the Kvaldir into mist over time. All that remains are patches of sea growth that had accumulated on their bodies and, of course, any loot they were carrying.

Culture
Sea vrykul live in clans and presumably worship the Elemental Lord of Water, Neptulon.

Trivia

 * Sea vrykul can breathe underwater.
 * Tuskarr believe sea vrykul are angered spirits of slain vrykul.
 * They appear to be based on the recordings of vikings having used mist as a way to mask their movements and create sneak attacks, which the kvaldir seem to excel at.