clawing at the walls of my enclosure. what people refuse to understand is that light wasn't destined to be a terrible person, but instead that the moment he put a pen to the death note, he was Doomed. even if no one knew that he had killed otoharada he knew, light, son of soichiro, who pursues justice above all else, is said by the author to be The Only Good Person in the Series, light yagami with loving parents and a sister whom he wanted to protect above all else. HE killed someone and HE knew and even if he wanted to say it was just a coincidence it sunk into his psyche. if anyone found out it would tear his family apart. that is the stone that sunk into him and that is the death note's curse. You Killed Someone and Only You Know.
and then he saves someone with it. he saves a young woman and that's the second nail in the coffin because now he has a reason and that reason aligns with his belief system. and so, already traumatized that he has now killed Multiple People and Cannot Say Anything without ruining his life and also traumatizing his entire family, he has no choice but to keep going. and then kira gets a following. people are encouraging him and he's already being followed by a supernatural being so yeah, sleep deprived and malnourished and in contact with A Death God's Book, pursuing godhood and protecting the innocent becomes the only way forward as he is pushed Further and Further from humanity.
and then the police start pursuing kira. now he's isolated from both sides—kira's followers continue to push him upwards and deify him, while the police (!!! his own father !!!) proclaim him as evil. he couldn't let anyone find out before but now it's even More of a risk, now he has to actively evade capture, dedicate his time and energy to hiding away and isolating himself further and further and further
and then misa appears and it only gets worse, because SHE idolizes and deifies him, so while he does have someone to confide in, it's again someone who will reaffirm that he's right every single time, because He Helped Her. he avenged her parents and so now all she has is him. and all he has is her. and the isolation gets Worse
L is the only person who gets even CLOSE to reaching out to him, poking and prodding at him and tugging at his strings at a very close and personal angle. it's said in L change the worLd that L lost because kira died without realizing the error of his ways. the intention was to bring him back down to earth!! to atone!! not just the death penalty, not just jail for life, to bring him back down to humanity!!
but L dies, and that tie is severed, and from there it only gets worse, because then kira's actions begin hurting his family. but now there's a religious movement, there's countless supporters who want kira to continue, who revere kira as their god, so even as sayu is permanently scarred, even as soichiro dies, he can't stop. because if he stops, all of it was for nothing. because kira has existed for years, he's been lying to his family for years, L was right and he's wasted years and years of his life so he HAS to keep going, until the moment it puts him into the ground. because there's no going back without putting the entire world against him.