He wants it for the same reason I don't want Misho to have it: it's an anti-death-magic "I Win" item. If Misho gets his grubby mitts on it, and it still works like the legend claims, then Misho will be an immovable object against The First and Forsaken Lion's unstoppable force. As we all know, in Exalted, Defense Trumps Offense
"No Thing Born of Death Has Power Over Him". Scary, even for a god.