Koshchei, also Kashchei, often given the epithet "the Immortal", or "the Deathless", is an archetypal male antagonist in Russian folklore and mythology.
Kashchey the Immortal by Viktor Vasnetsov, 1848–1926
Koschey revived by Ivan with water, from Marya Morevna (The Red Fairy Book, 1890)