Ivan the terrible after fighting and losing he realized he lost but instead of giving up and disappearing like in fgo he was determined not to die not to lose he thought he couldn't lose so with the last of his energy he started to walk away trying to find someone who he could give his heart to so they could take his place and take back his spot as the lost belt king in his time desperate needs he found a boy injured and at deaths door step at him the boy was Russian it made everything perfect and he gave the boy his heart and y/n accept it and y/n was now known as Ivan the Terrible or the thunderous emperor