"We have? When the hell was this." Mephisto joked halfheartedly, though what Ariel said made him feel sunk again. "What do you need, Ariel? I have my hand in everything, I can find anything. If you can't find it, if it's gone for good, I will drag it from history itself."
Maybe he was hellbent on this, or maybe he truly wanted to see if Ariel could even do what he said. Even Mephistopheles didn't know anymore, which was more important.