"You will always be my butler."
"Yes, my lord."
Under the setting sun, before the missing moon, does the agreement between the devil and the boy represent an eternal bond or a fleeting happiness?
When there is only that blue in his red eyes, he is the only one in his world.
Even if I forget everything and come to a strange world, I will still fall in love with you. This is our bond, a bond that will not fade away with time.
Maybe, we really can be eternal.