Lord Strahd

Background
Strahd was once a man, who somehow eventually made his way into the land of Barovia. Strahd, and his younger brother Sergei and his lover all found themselves within the Castle Ravenloft.

Strahd wished for his brothers lover to be his bride, but she rejected him, and in rage he killed his brother. Hoping to marry his brothers fiance, she killed herself out of grief and disgust on her wedding day, as Strahd was then killed by guards (as seen in Arannis Galandal's vision), The Dark Forces resurrected him into a vampire, and he then proceeded to kill everyone at his brothers wedding. Strahd, a broken man, began capturing helpless women, in an attempt to imitate his bride. He trapped the inhabitants of Barovia and surrounding areas inside of the Dread Plane, making them stay with him, undying, forever.

At some point, Strahd began bringing Adventuring Parties from the Material Plane to the Dread Plane to test him. One of these parties being the Lost Tides. It is unknown what happened to them, and whether they did escape.

Growing bored of these games, he knew that the Dark Forces wished for Ada Mistborn; his great (x10) niece, to become his heir, her dark and cruel personality being a perfect fit, for when Strahd even in his immortal life could take no more. Strahd however, wanted someone else. A better fit. A Moon Elf, for example.

He also, at some point, captured The Lost Tides. He sent Zhoran to be ripped to shreds by the werewolves, gave Gaelin to an old witch, Isolde escaped as Strahd wished, before locking Torment away, unable to break her resolve. However, Caidove, having not taken her potion for a number of days, became a vampire and began serving Lord Strahd.

Interactions With Mystic Obscura
Strahd sent his mists to capture the Heir he wanted; Arannis Galandal. He set up the elf by making sure one of his vampires pretended to be a human, and led him around a merry chase through the halls of Ravenloft. Arannis eventually confronted Strahd, who informed him that he had a task for him. If he completed the task; which was to perform sacrilege on a church Strahd's forces had been unable to enter, then Strahd would let him go. If not, he would kill him, and send him back to kill the rest of his party; presumably as a vampire.

Strahd was pleased when Arannis agreed, and upon completing the task, revealed a twist. Arannis had to sign a contract that would make him Strahd's heir, or he would make sure his friends suffered and died in terrible ways. Arannis agreed, signing the contract as Strahd gave Arannis an amulet, one that was Ada's, to make sure she knew what had happened.

After Plink's death, Strahd was surprised that magical forces had brought her to him, making him break the contract with Arannis, and instead forcing Plink to become Dark Lady. He stated he didn't know why this was happening, but he'd take what he could get.

Strahd stole Eloithe for unknown reasons, upon her death, reviving her with The Abbot's help before locking her in the dungeon, probably in an attempt to break her and have him join her. He sensed when Mystic Obscura arrived, sending Caidove to find them. She did, and tricked them to join her in defeating Strahd and finding Eloithe. However, Strahd's plan backfired, and he was killed by Mystic Obscura themselves, for some reason unable to regenerate or return, unlike Caidove, who escaped in her mist form.

As Strahd died, Barovia, for a time, returned to the paradise it should have been. However, it was stated by Caidove months later that Strahd was in fact alive, as you couldn't kill death itself.