Kosch’ei the Deathless is another handsome character of the Russian mythology, too dark & too creepy. I believe that he is the most complete reflection of Evil we have. Traditionally he is represented as an old ugly man, who loves young beautiful maidens & has great dark magic powers. He always abducts them. He seems to be immortal, no hero is able to kill him with ordinary weapons, however Koschei’s death exists. This is a needle hidden in an egg insides of a bird or an animal, locked in a chest hanging on an old tall tree somewhere in the heart of the forest. So, to win Koschei the hero must fight him in person, then to discover the proper tree, to be able to unlock the magic chest & to be fast enough to kill all the enchanted creatures to get the desired needle. Too often there is a thunderstorm after the last one is broken. This is a sign that Evil has been defeated.
No matter its weird nature, Koschei’s personality is very curious to be examined as it symbolizes the Time & God Saturn in all his apotheosis. As well this spirit is the Lord of the Darkness and the Underworld. He reminds us of a perishable nature of matter (by means of his inventions to hide his own death) & of a power of all supernatural (enchantments he uses to keep him alive & to seem powerful).
In many tales Koschei is considered to be Baba Yaga’s friend & even her fiancé, but I can hardly remember any one where they join forces to double the Evil. Baba Yaga’s attitude to him is rather liberal. She supports him but up to the certain moment. As a rule in the climax of the story, when his evil seems to overpass the limits, she begins to help the hero & saves all. Her assistance reminds us of a balance the Time needs to keep the world in its place.
Koschei the Deathless means a secret, a dark mystery & unknown. Facing it is to obtain a new experience, to grow up. Each of us passes this darkness sooner or later in life to come to a new sunrise of existence.
More about Koschei: https://en.wikipedia.org/wiki/Koschei