Ivan Bilibin

Ivan Bilibin, Illustration for the tale "Vasilisa the Beautiful", 1900

In Slavic folklore, Koschei is an archetypal male antagonist, described mainly as abducting the hero's wife.  Koschei is also known as Koschei the Immortal or Koschei the Deathless.   Koschei cannot be killed by targeting his body. His soul is hidden separate from his body inside a needle, which is in an egg, which is in a duck, which is in a hare, which is in an iron chest, which is buried under a green oak tree, which is on a island. As long as his soul is safe, he cannot die.

Ivan Yakovlevich Bilibin Koschei the Deathless Illustration for the Russian fairy tale Marya Morevna