What he said to jennie did not cause her to kill herself. Her facing reality is what did. It wasnt his fault and she was already depressed that was just the cherry on top for herself. Also ud be surprised how hard it is to tell someone the truth when the person in this case Jennies truth is the only thing thats making her happy. N even then he told her yet she passed it off. Hes not selfish, i dont even see how he is. Now on the other hand the seme does have a bad personality like u said
Jenny had a mental illness, the way he said the truth to wasn't the good way to do...you don't bring harsh reality to someone like that... every word he said had an impact and the distance he put too...i said he is selfish because he wasn't feeling bad for his friend but he felt bad because the seme didn't recognise him , the moment he knew he wasn't special at all that why he said it...that also why he said he betrayed his friend. His revenge is all about the fact that Jenny did tell the truth about the letter knowing himself that it wasn't the seme's handwriting... that's show how he did it only for himself...this is an crazy obsession...also the seme his crazy...at the end everyone isn't normal at all

The uke is weird, he knew the seme wasn't the one who wrote those letters, pushed his friend because of his own frustration ( the seme didn't recognised him and the fact that he thought he was better than that girl because the seme did talk to him ). She committed suicide and then he was looking for a culprit knowing what he said to that girl made her kill herself.the seme has a really bad personality but the uke is selfish irresponsible and in a denial condition. You can't force people to remember you and can't push you feeling on someone... that's is how life is