I love writing Shen Qingqiu (Jiu edition), he's so terrible and yet I can't help but adore him; something about the wretched tragedy of his life and story really grips me, all the bitterly ironic near-misses of fate, the dedicated slog towards misery and death, the self-fulfilling belief in his own innate wretchedness and failure to understand that "naturally pure" doesn't actually exist, that nobody else innately knows what it means to be "good" either and that they also often make horrible mistakes and harm people, and are merely doing their best in spite of it.
I've thought about it a lot, and he seems to believe that since he doesn't innately know how to be kind and gentle-- that because cruelty comes easily while kindness is difficult and unpleasant and feels frightening and therefore enraging, that because he's jealous of his own adult self and the children under him, that because he has the desire to hurt others-- that he's INHERENTLY bad, and therefore there's no reason to bother trying to change or resist it, because people are either born good (like Yue Qi) or wicked (like Shen Jiu) and that's all there is to it. He NEEDS to believe that, on some level.
He has an extremely black-and-white view of the world, just one aspect of which is his absolute intolerance for demons, even greater than Liu Qingge's. I believe it's just one more effort to reject himself, ultimately. He's so convinced of his immutable other-ness, his worse-ness than everyone else, his ugly corruption in comparison to his idealized notion of Yue Qi's shining purity, that it becomes a bottomless swamp he can't escape on his own but that also threatens to pull in unwary bystanders and would-be helpers.
