Now, this is a Saturday D & D post, but for the record, recurring villains are a lot more than just a part of a story-telling game. Toxic people who have it in for you occur in real life almost as often as they do in fantasy story-telling with villains who are often orcs.
But unlike insurance adjusters, city pool inspectors, and bank representatives, the villains in a D & D game are severely challenged to survive a single adventure. Yes, the player characters are constantly on the lookout to slay the dungeon master’s recurring villains so they can’t recur without being raised from the dead. No matter how much you hate that unfair insurance guy, you are not allowed to slay him with a sword.

Mallora is not a sexy female villain… more like vile.
Mallora was a lucky witch woman. She was one of three agents of Karnak, the Vampire Kingdom, who were trying to thwart the player characters as they sought lost technology in the wastelands of Cyre. She was a second level sorceress at the time, capable of only a couple of basic-level necromantic spells. She was a part of the evil organization known as the Emerald Claw, a sort of religious cult built around worshiping the undead, and had an evil dwarf fighter and an evil archer to help her trap and kill the heroes, along with about six animated skeletons who, at second level, are one-chop minions that go down in the first round of battle usually.
The green haired witch successfully trapped the heroes in the mists of Cyre and the dwarf and the archer were taking their toll when Gandy rolled a twenty and not only nailed the archer in the eye with a crossbow bolt, but made the archer’s shot go awry and hit the dwarf in the back of his bald head, shortly after Fate had knocked his helmet off. So Mallora cast another concealing fog spell and ran like a little green rat directly away. She survived to haunt them another day.
This she did as a member of Brother Garrow’s Emerald Claw crew in the next adventure where the heroes had to track down a friendly agent of Breland who had been turned into a vampire. She was eighth level at that point, just like the adventurers themselves, and a much more dangerous adversary. She didn’t prevent the characters from capturing the rogue vampire, and she did some damage, but managed to slink off unharmed once again.
She would enter the player characters’ lives one more time in the jungles of Xendrick as the mini-campaign was reaching its climax. She and Brother Garrow pursued the heroes through the jungle to the giant ruins where the monster construct Xulo would finally be brought to powerful and evil life in a necromantic ritual. Brother Garrow definitely met his end in a spectacular fashion, being sucked into another dimension through a keyhole trap set by giant mages a millennia before. It was gruesome.

Garrow before his transformation into a toothpaste-like substance
Mallora was aboard the Emerald Claw’s flying skiff as it chased the airship the heroes were themselves aboard. A well-placed fireball by Druealia the Wizardess took the skiff down to crash into the jungle below with a fiery explosion that should’ve killed all aboard, including Mallora. But is she actually dead this time? They didn’t see her die. So only the dungeon master knows for sure. After all, what good is a recurring villain if they don’t recur?