Seems to be an unpopular opinion here, but I love his character. Yes, Xie Qingcheng is not obligated to love him, and in true selfish-younger-man-has-a-love-hate-complex-with-indifferent-older-man-with-established-position-in-society fashion (a surprisingly common trope), a good amount of his life is thrown into disarray by He Yu, and specifically He Yu's pursuit.

But I think the genius in He Yu is the messaging behind his actions, both the bad (very bad) and the good. His unhealthy attachment to Xie Qingcheng completely makes sense given his life experience and the RN-13 in him that makes him extremely dangerous and volatile when emotional. Just like how people react to criminals with mental disorders granted asylum out of consideration for their circumstances, many readers will probably be resentful of He Yu's eventual happy ending, believing that he doesn't deserve the leniency that he gets.

Xie Qingcheng has lived a life so tragic it's almost impressive, especially that he managed to have all that happen in thirty some years. He Yu, by comparison, seems like he's throwing a hissy fit over something trivial. However, an utter lack of love is not trivial. There have been so many stories of how children deprived of affection develop severe mental trauma, and when exacerbated with the whole drug business, would totally result in someone as unstable as He Yu. With regards to their relationship specifically, I don't think Xie Qingcheng has done anything wrong and shouldn't have been treated like that--it's really the Mandela Organization's fault, for intentionally ruining his mental state in so many ways to weaponize him. You can say that Qingcheng deserves better, but I understood their relationship to be that of two misunderstood individuals who will never have the chance to be as close to anyone else in the world as they are with each other. They will always have a connection, no matter how twisted, and I interpreted the story as them untangling all the knots and aiming to get rid of all that buried toxicity. Is it painful? Extremely so, but their circumstances force their hands. I can't help but feel pity for these two who should've had a much kinder ending.

He's a rapist. He's self-centered, often cruel, and blinded by his own emotions. He's a bad person. But he was made that way, by the people who never gave him a chance not to be a monster. I think that's meatbun's message about mental illness in this story, one that should be shared by more people.

it's happy ending, don't worry. After so much pain it's worth it

You need to believe He Yu, also the last chapters before end it's absolutely crazy get prepared for tissue

seeing the way he refuses to hurt others except Xie Qingcheng (he'll regret hurting him), due to his confused feelings for him.

The conflict of the murders and RN13 plot feels like it fights to be the main conflict with the love conflict between He Yu and Xie QingCheng which is not necessarily bad, but feels like a lot of back and forth and goes from the seriousness of death to He Yu and XQC dealing with illness to He Yu pouting over their relationship. It's a lot to go back and forth between and I had to take breaks between chapters often just to get myself back on track with whatever was happening next.

The story is extremely slow-burn, and at the core of it, it is a story about redemption. How two broken people destroy each other but finally find redemption in the other. The characters development are really satisfying, both become a better self because of each other at the end of the story. And it's a HE.. HE!!