The possibility that keeps him up at night is that Meng Yao came into his service an honest man, and over time changed into what he sees before him now. That, as his ambitions rose and his world grew grander, he reshaped himself and discovered the things he was capable of, all the while looking like his familiar self, but transforming under his skin into something Nie Mingjue could hardly recognize.
Of all the prisons in which she's spent time, Lotus Pier may be the kindest.