[His eyes narrow as his expression returns to something more familiar as anger -- though it might be hard to tell exactly what it is Rin said to inspire it. He allows him to finish speaking, but by the end of it, he's reached the limit of his patience.]

And just how long has that been? A month? Maybe two? I'm not asking you this because I think it will be necessary in the coming days. I'm asking because I know it will be in the coming years.

[Mephisto played the long game, setting "investments" for the future in his allies. It's not that he thought any of the cram school kids had the potential to be worthwhile allies now -- but by nurturing that connection, he could guarantee reliable allies in the future.]

[But something like that was easier said than done. Especially when it required someone like Mephisto to present as someone trustworthy.]

And in any case, allies are good for more than just fighting... but it doesn't matter. I'm not going to stay here and argue with you. Or perhaps I should remind you again that you followed me here.