Light's relationship with his father is such a heartbreaking multi-faceted tragedy to me I hate it so so so much.
Soichiro loves his son so much, and while he's certainly not a perfect father I know that he cares deeply about Light. He wants to prove Light's innocence so badly but he can't let go of the underlying doubt that he might really be Kira and it gnaws at him. He does not know that from the very beginning he was being used by Light, whether it was to obtain information about the investigation, or to get to L, or to strengthen the foundations of his own lie that he wasn't Kira, this entire time he was simply another resource. He'll hang onto this doubt for years, even after L is dead, even if he doesn't express it in the latter half of the series, until he himself is on his deathbed, with what he believes to be undeniable proof that Light isn't Kira. (It's a lie, of course.) He dies happy, but it's on the foundations of blissful ignorance. His own son brought him here, brought him to the point where he had to sacrifice half of his own remaining life span, to his own death march, and was still trying to use him even now to kill someone else, but he doesn't know that. Soichiro said that what was evil was the power to kill others, and that whoever used it was cursed. Light was that cursed man, of course, and he tried to bring that curse onto Soichiro too by making him kill in his last moments. Soichiro was happy regardless, because he didn't know. He'll never know. (In the manga/anime at least. More on that later).
Light loves his father but it's not enough to turn him away from the terrible decisions he's made, if anything it only fuels them. His idea of "justice" is a twisted model of what he parroted from Soichiro, and he uses his father as another pawn (and a powerful one at that) in his plans. If he can prove that Kira is justice then perhaps his father will no longer call Kira, and therefore Light, evil, so he just needs to ensure that Kira becomes justice, right? It's Light's own actions that land his own father in the hospital for a stress-induced heart attack and yet he says only a few minutes later that he's the happiest he's ever been in his entire life. Even after Soichiro denounces Kira by calling him evil, even after he calls the Death Note's power evil, even after he unknowingly tells Light that he is cursed. When Soichiro dies Light is too deep in his own plans to actually properly process the fact that his own father is dying past what it means for his goals, but at the same time he still cares enough that after the fact he'll genuinely cry, only to brush it all away later. (Personally, I don't have a single doubt in my mind that Light's crying in that scene was genuine and I Will die on this hill). Soichiro had unknowingly denounced Light one last time just before his death, openly relieved that he "wasn't Kira after all", which also reveals that he has had doubts about Light this entire time, even after L died. By the time he's caught at the Yellow Box Warehouse Light will have denounced his father too, seeing him as someone who was made to be a fool, someone who was naive, even, too earnest for his own good. He won't realize that part of this description of his father might have applied to Light himself, back when this all started. Light takes after his father so much in so many ways already, so why not in this way too?
Ough. And honestly the other adaptations never miss out on this tragedy either, and I love them for that. (spoilers for the musical and 2006 live action movies I guess?)
In the musical we see Soichiro express his doubts and conflicts about who to believe, Light or L, if the son he raised really is a murderer, if everything he knows about him is just a lie. Like, there's an entire song about this, and you can tell how torn he is about it all, how badly he wants Light to be innocent but about how he also needs to face the truth no matter what it is, but at the end of it all he doesn't even get the answers he wants. At the end of the musical the only thing he finds is two corpses, Light's and L's, with no answers. No last words, no closure, only dead ends and a dead son and a grieving daughter. It's so awful I hate it here.
And the live action movie is fucking Insane. Like, wow. Okay. (Spoiler for the ending of Death Note The Last Name I guess) In the 2006 movies/novels Light writes Soichiro's name in the Death Note himself, and it's such an inconcievable move that it leaves even Misa shocked; Light tries to make Soichiro give him the Death Note for the last part of his plans, seeing his death as a "necessary sacrifice" (insert tangent essay about why I think 2006 live action movie Light is actually the most "coldhearted" Light Yagami, despite how infamous anime Light is). It doesn't work, and Soichiro does end up finding out that Light is Kira this time, and they have a confrontation, but he doesn't even sound truly hateful towards Light for it. He Never seems to outright hate Light for it, even after Light calls the whole confrontation a waste of time and instead tries to continue killing with the piece of the notebook in his watch, even after he tries to get Ryuk to kill everyone. When Ryuk inevitably writes Light's name and he collapses, Soichiro still reaches out for him and holds onto him as he's dying. Light literally dies in Soichiro's arms, still looking for the validation that he was right, that this wasn't all for nothing, that he was doing the good thing, trying to make Soichiro understand that he was trying to enact justice based on what he learned from him in the first place. Soichiro not only learns but sees for himself what his son has become, and Light dies in his arms leaving no closure for either of them. Soichiro will announce Light's death in L Change the WorLd on the news without saying his name, saying instead that it is only Kira who is dead, even though he and Light are one in the same. Sachiko and Sayu will never get to know the full truth about what happened to Light, instead Soichiro will lie and instead tell them: "Light was killed by Kira."
And then holy Shit the jdrama. If I write about it here this post is gonna literally double in length and also I don't really wanna spoil it but. Man. Man. If you watched it you know. Holy Shit dude I Cried.
It's the fact that, canonically, Soichiro will die oblivious to what Light has done, but even in the instances where he does find out, it doesn't make it any better, and it doesn't make him love Light any less, it just gives him more to grieve.
It's the fact that there isn't a single universe where Light doesn't use his father for his own gain, whether to gain information, or to try and control him with the Death Note, or make him write in the Death Note himself, and not a single time will he realize just how far he's strayed from Soichiro's ideals, and not a single time will he not forsake him for it by the end of the story.
It's the fact that, despite everything, Light will always refers to Soichiro as "dad/my dad" (informal) rather than "father/my father", even after he has been "denounced" (and this is true in every language that Death Note has been translated in, as far as I could find. Man, isn't that so cool! :) <- Through tears).
Anyways that's what I've been thinking of how's your guys' days going
