Koshchey or Koschei, often called “the Immortal” or “The Deathless” is a supernatural antagonist in Slavic Mythology. He has the look of an ugly bony old man, and he is dangerous mostly to young women.
Usually, he takes the role of a malevolent rival father figure, who competes for or entraps a male hero’s love interest.
His name is derived from the ancient Slavic word “Kosh” meaning something very skinny or sapless. In the modern languages his name resembles the word “kosť” most closely meaning “bone” in Slovak.