Other option could be to use the name of an undead creature from folklore.
en.wikipedia.org
A
Fext is a mythical
undead creature in
Slavic mythology. Its origins are found in the terrors of the
Thirty Years' War (17th century) in central Europe. It is said that the Fext is invincible to bullets, except bullets made of glass. Some of the great generals of that time were called Fexts because of their assumed
immortality.
en.wikipedia.org
Upiór (Tatar language:
Убыр (Ubır), Turkish: Ubır, Obur, Obır, (modern Belarusian: вупыр (
vupyr), Bulgarian: въпир(
văpir), вампир (
vampir), Czech and Slovak:
upír, Polish:
upiór,
wąpierz,
wupi, Russian: упырь (
upyr'), Ukrainian: упир(
upyr), from
Old East Slavic: упирь (
upir')) is a demonic being from
Slavic and
Turkic folklore, a prototype of the
vampire.
[1] It is suggested that the Ubır (Upiór) belief spread across the
Eurasian steppes through the migrations of the
Kipchak-
Cuman people, after having its origins in the regions surrounding the
Volga (İtil) River and the
Pontic steppes. The modern word "
Vampire" derives from the
Old Slavic language and
Turkic form "онпыр (onpyr)", with the addition of the sound "v" before a large nasal vowel (on), characteristic of Old Bulgarian, as evidenced by the traditional Bulgarian form впир (vpir). (other names: onpyr, vopir, vpir, upir, upierz.)
[2]