Fiends of the Eastern Front, created by Gerry Finley-Day and Carlos Ezquerra, originally ran in 2000 AD progs 152 to 161 in 1980. It told the story of Hans Schmitt, a young German soldier in World War II who discovers that the Romanian soldiers who are fighting alongside his unit are actually vampires under the command of the evil Captain Constanta and his second in command Sergeant Gorgo. Schmitt and his comrade Karl Mueller find themselves at more risk from the vampires than from the Allies.
Though originally a self-contained story, a follow-up series later appeared in the Judge Dredd Megazine and the Fiends have appeared in a series of novels by David Bishop. They also turned up in Mega-City One, thanks to malfunctioning dimension warp technology, in the Judge Dredd story 'Helter Skelter' by Garth Ennis.