Death Knight Name Generator

A death knight is a warrior who died in service and came back wrong, so the best names carry two layers: the respectable knightly name the character had in life, and the cold or corrupted surname death gave them. The genre's template is Warcraft's Arthas Menethil, a crown prince whose name did not change when he took up Frostmourne; alongside him stand Darion and Alexandros Mograine, Thassarian, Koltira Deathweaver, Orbaz Bloodbane, and the Four Horsemen of Naxxramas (Rivendare, Blaumeux, Korth'azz, Zeliek). Dragonlance gave D&D its archetype in Lord Soth, and Warhammer's Blood Knights add Walach Harkon. Notice how often a perfectly ordinary given name (Darion, Sally, Thoras) is paired with a grim epithet or a family name tied to a fall from grace.

Original death knight surnames lean on a small vocabulary: frost and rime for Scourge-raised knights, grave, bone and ash for the undead generally, mourn, sorrow and hollow for the tragic ones. Titles matter too, because death knights are almost always ex-nobility or ex-clergy: Highlord, Knight-Captain, Baron, Dame, Ser. For non-human knights, start from the race's phonology (orcish Gorthak, elvish Sylvaren, dwarvish Thormund) and attach the cold surname.

If you want the character to feel like a person rather than a monster, keep the first name human and let only the surname or title show the rot.