Koschei the Immortal — Russian fairy tale character
Koschei the Immortal, an evil monarch, is usually depicted either as a scrawny old man or as a king on horseback. He is not completely immune to death – he can be killed, but to do so you need to break a magical needle, which is hidden in an egg, which is in a duck, which is in a hare, which is in a chest in an oak tree. There’s an alternative version of the story, in which a stallion brings death to King Koschei. His tale is a sad one; one of his stories, “Koschei the Warrior,” tells how he had once been a warrior but was betrayed by his comrades and taken prisoner by his enemies.
After many long years, he was able to break out of his rusting chain armor and started to take his revenge. Several versions of the Koschei story have him imprisoning women, usually the betrothed of the young heroes of the tale. This is the version we find in tales like “Koschei the Immortal,” “Maria Morevna” and “The Frog Princess.”