I have NEVER seen my own character as a person reflected so clearly through the actions of one in media before. I can basically write Priest's entire mental character arc / internal struggles from this point onward verbatim. The first time, PNC hits like a freight train, and the memories of yourself spouting off your dedication and resolve to virtue bubbles like acid in the already gaping wound. You'll wish you'd never done it, wished against all reason that you somehow could've known beforehand the dejection that you'd feel, all to no avail. At some point your emotions will be drawn out to their logical conclusion and you'd come to terms with the fact you couldn't have known. And then you'll wish that's where it ended. You'll wish that you could just wholeheartedly accept Dante's words, to just believe them, but regret and shame hang over you like a storm cloud. And it's not even like you can eliminate the feelings that pushed you this point. It's not like you can turn off the part of your brain that feels sexual attraction, and once you've proved that you are capable of something, there is no going back. With fuel and oxygen in such high abundance, it takes only the most minute of sparks to burn down everything.
I'm going to go there and compare this to Berserk; if Berserk is an illustration of what it's like to be a man with issues, this manga illustrates what it's like to be a teenage boy with issues.