[Nah, this is Rin he's dealing with. The last thing he'd expect is heavy consideration. Which is probably why there's not nearly as much effort going into his words as when he struck that deal with Izumo on Thesa Station.]

[Of course, he's also just in a piss-poor mood right now, so--]

...oh we weren't, were we?

[And with a poof, Mephisto is back to himself -- but now standing a short ways away, looking entirely unimpressed.]

Then perhaps you ought to take a moment and consider just who it is you have to thank for giving you the opportunity to live a normal human life [He points down at Kurikara.] by sealing your demon heart within that blade in the first place.