[Briefly, he wonders if perhaps these words aren't also a reflection of Arahabaki's heart as well.]

[Curious green eyes stare back into soft, almost desperate blue ones. It's not entirely unexpected to see this sad and lonely side of himself that Chuuya must have been keeping locked away in his heart all this time. He's reminded of a particular student of his, whose heart also ached for emotional connections she convinced herself would only become a hindrance-- when really, she was shielding her heart from the pain of one day losing those connections. A girl who felt so thoroughly betrayed by those she loved that she sealed of her heart from everyone.]

[It's rather fitting that both she and Chuuya became allies he vowed to never tell a lie to. Is there perhaps a traumatic breach of trust in Chuuya's past as well?]

[Gloved hands sweep upward to cup around Chuuya's face, keeping his gaze fixed on his own as Mephisto looks back into those searching blue eyes.]

So long as our agreement remains intact, I will keep you as my familiar. And when the day should come that you breathe your final breath, I will make sure you do not have to face that distant horizon alone, and shall bid you farewell as you cross to the other side.

[If he getting a little theatrical here? Maybe a little. But even with Chuuya under the effect of the monkey's spell, Mephisto is still speaking the truth with every word that falls from his lips.]

You needn't ask to be given a purpose. I saw your potential the moment I laid eyes on you-- and have sought to make you mine all this time.

You won't have to wander all alone anymore.