Likes: Young women, stimulation
Dislikes: Boredom, heroes
Talents: Cheating death, contradictory reasoning
Natural Enemy: Ivan Tsarevich, Baba Yaga
Height: 214 cm
Weight: 50 kg
Weapon: Sword
In contrast to the villainous womanizer shown in legends, Koschey is actually rather low-key. Koschey suffers from a bone-deep ennui, born of worry that the immortality that he sought isn’t all it’s cracked up to be. Thanks to the information that the Grail grants to summoned Servants, he knows much more of the world than he did in life, which has brought doubts to his mind. An immortal being would eventually succumb to boredom, having experienced all that the world has to offer. Thus, he spends most of his time thinking, pondering his fate.
As such, usually Koschey will simply sit around, perhaps using his abilities to observe the goings-on of the world, seeking something to occupy his attention, not even bothering to use his Noble Phantasm to preserve himself. He will still remain even if his temporary vessel is destroyed, so any additional effort on his part is meaningless (or so he has convinced himself).
However, the person his legend was based on still exists inside Koschey, waiting to be roused. Should something rouse his interest, this part of his character would inevitably be brought forth, showing the ‘true’ face of Koschey the Deathless. There is virtually no chance that participating in a Holy Grail War wouldn’t pique his curiosity and rouse him from his ennui. Never-before seen magics, weapons both holy and demonic, gorgeous women and insolent heroes are a Holy Grail War’s stock and trade, after all.
This Koschey seeks simply to enjoy life. And outside of womanizing, he enjoys crushing heroes most of all, especially those that would prevent him from doing what he wills. He is completely willing to utilize underhanded tactics in battle, and the outrage it provokes in heroes simply brings him more joy. Outside of a direct threat to his weakness, he is supremely arrogant, caring little for even Noble Phantasms targeted at him. After all, he won’t be killed.
In addition, as existence has once again proven itself worthwhile, Koschey will do his utmost to keep his spiritual core safe, so he can enjoy the world for all its worth. Once properly motivated, Koschey will immediately activate his primary Noble Phantasm, and if at all possible, will hide his spiritual core on the island of Buyan, laying as many protective magics upon it as he can. Failing this, he will instead seek another location he deems secure enough, using his abilities as a Caster to make it even more so.
In both his moods, Koschey craves stimulation most of all, something to occupy his interest and give him hope that his ennui can be kept at bay. Thus, his wish to the Holy Grail would most likely take the form of a world that he can explore for eternity. He would not wish for immortality, seeing as he has already achieved that by himself.