How to build a believable vampire name
The main mistake is choosing modern names for immortal characters. If your vampire is 600 years old, they can't be called "Brian Smith". Names should anchor to the conversion era: a vampire born in 1300 carries medieval name (Bartholomew, Eleanor), one from 1700 carries baroque name (Sebastian, Aurelia), one from 1900 may have Victorian name (Vincent, Cordelia). That temporal coherence defines the character from first mention.
The noble particle adds class and geographic origin. "Lucien de Sangremort" sounds French aristocratic, "Vladimir Drăculești" sounds old Romanian, "Sebastian von Volmir" sounds Germanic. Mixing particles and houses from different regions (Vladimir de Sangremort) creates cultural noise unless you justify dynastic marriage.
The ancestral house is where most go wrong choosing too-obvious surnames like "Bloodfang" or "Darkmoon". Better to use real toponyms with gothic resonance (Carpathia, Brașov, Sibiu) or Latin names (Tenebrae, Crepuscule, Lacrimosa) that sound elegant without caricature. Interview with the Vampire uses "de Lioncourt" for Lestat: aristocratic, French, no cliché.
Vampires by game system or narrative universe
In Vampire: The Masquerade, the clan defines name style. Ventrue prefer Anglo-Saxon power names (Hardestadt, Strauss). Toreador choose European artistic names (Helena, Pierre). Tzimisce keep Slavic and Romanian roots (Vykos, Sascha). Brujah tend toward revolutionary or ancient Greek names (Theo, Smiling Jack). If you play VTM, respect the clan: it breaks immersion when a Nosferatu is called Christian.
For D&D 5e, vampires are undead humanoids without specific naming tradition. Strahd von Zarovich (Curse of Strahd) sets the pattern: Slavic first name + Germanic particle + toponym. "Mircea van Brașov", "Aurelian von Drăculești" follow that formula. For lesser vampires and spawn, you can use simple names without particle. Only ancients carry house and title.
In modern literature, Twilight breaks the rule: the Cullens have modern American surnames. It works because the genre is contemporary romance, not gothic horror. If your novel is modern urban fantasy, you can use common surnames with slightly archaic first name. The Vampire Diaries uses "Salvatore" (elegant Italian surname but not exotic) with American first name. Choice depends on tone: classic gothic asks for grandeur, modern asks for subtlety.
Typical mistakes when naming vampires
First: too-long names. "Sebastian Aurelius Maximilien de Sangremort von Drăculești III" is unreadable and sounds like parody. Limit to three elements: first name + particle + house. The title (Count, Duke) is mentioned in formal introduction but not repeated each time. Bram Stoker's Dracula is only "Count Dracula", not "Vlad Drăculești III Prince of Wallachia".
Second mistake: mixing languages without logic. "Hiroshi de Sangremort" sounds dissonant unless you justify how a Japanese vampire ended up in a French house. Better keep coherence or use the mix intentionally to show exile or adoption. Far East Ventrue in VTM have either pure Japanese names (Asanbosam) or fully adopted to destiny (Yoshiro Hamasaki).
Third mistake: blood/dark/moon surnames repeated to exhaustion. Bloodmoore, Darkraven, Nightthorn, Bloodfang, Shadowmoon. After three characters like that, everything is the same. Better use real toponyms (Prague, Carpathia, Wallachia) or subtle Latinisms (Atramente, Tenebrae, Solanum). Castlevania solves this with "Belmont" (real surname of vampire hunters) that isn't even vampiric, creating irony.
Vampires in culture: references for your name
The vampire canon starts with Sheridan Le Fanu's Carmilla (1872): the protagonist uses "Mircalla, Countess Karnstein" as anagram of Carmilla. That idea (names changing with each rebirth keeping letters) is brilliant for long sagas. Your 800-year-old vampire may have been Mircalla, Carmilla, Millarca, all anagrams of original name.
Bram Stoker's Dracula (1897) establishes Count + toponym format. Anne Rice in Vampire Chronicles invents modern vampire onomastics: Lestat de Lioncourt, Armand, Marius de Romanus, Pandora, Akasha. Note many lack surname: the oldest lost civil identity millennia ago. Only recent converts keep surname.
For non-Western inspiration: Chinese mythology has jiangshi (jumping vampires), Japan has nukekubi, Philippines has aswang. If your campaign includes vampires from different traditions, names respect those cultures. A jiangshi is called Liu Wei or Chen Hao, not Vladimir. That mythological diversity enriches long campaigns and novels with broad cast.