The Death Note franchise is known for its heated battle of wits between antihero Light Yagami and super-detective L, as well as many thought-provoking themes explored along the road. The original manga did an excellent job with all of this, however the Death Note anime changed or deleted things that detracted from the plot, notably Light's last demise in that dockside warehouse.
Both versions of Death Note conclude with Light/Kira's final defeat, with Ryuk the shinigami personally writing down Light's name to finish him off, however the anime version lacks several essential elements that make Light's defeat so sad to witness. Simply said, the Death Note anime eased up on Light, diminishing the effect of Kira's agonising demise.
How Death Note's Anime Killed Off Light With Dignity
Up to a point, the manga and anime versions of Death Note follow the same course, with Light confronting the cool genius Near in that warehouse, only for Light's final attack to fail, and both Light and Teru Mikami the lawyer are exposed as Kiras for all to see. From there, the two versions diverge, and the anime chooses the less distressing route. Light gets shot a few times, only for Teru Mikami's suicide to create a diversion and allow Light to flee the warehouse. As the sun beautifully sets, an injured Light Yagami runs across the urban landscape alone until he collapses on some stairs in another building. Ryuk the shinigami, having seen enough, writes down Light's name, and Light dies a relatively peaceful and dignified death.
This is different than the manga's material, possibly to make Light's final downfall less disturbing for viewers. It's common for anime series to sanitize or even censor the original material to tone it down, perhaps in case a youngster wanders into the room and sees the anime on the TV. By contrast, there's less risk of someone stumbling upon a manga volume's intense material. Death Note certainly takes this route, with the anime toning down Light's death to lessen the psychological trauma. In Death Note's anime, Light still gets shot and dies when Ryuk writes his name, but otherwise, Light dies in peace, almost like someone in a Greek tragedy, a surprisingly gentle way to end Light's antihero rampage. That makes sense from a production standpoint, but devoted Death Note fans know that the original manga offers a much more intense and thematically resonant conclusion to Light Yagami's story.
Death Note's Manga Fully Deconstructs The Arrogant Kira
The Death Note manga pulls no punches and tears Light Yagami apart as a would-be supervillain mastermind. He doesn't just fail to kill Near and the detectives, and he isn't just outed as Kira. Light has a full mental breakdown, overwhelmed by stress, fear, frustration, and desperation. This is shown to some degree in the anime, such as with Light's famous evil laughter, but the manga finishes the job. After Matsuda shoots Light, Light is unable to escape, and completely falls apart. He's undignified, panicking and making impossible demands of Teru Mikami and his fiancee Misa Amane, the latter of whom wasn't even present. Light's cool genius personality unraveled completely, and several characters, Ryuk among them, commented on it. Even Teru Mikami, who didn't kill himself in the manga, scorns the helpless, desperate Light as scum, not a god.
Light Yagami's desperation reaches new heights when Ryuk writes his name down, and Light spends his last 40 seconds in total denial of what's happening until the inevitable heart attack happens. The entire sequence is a fittingly disturbing and grim affair, deconstructing the seemingly perfect and brilliant Light Yagami as a helpless and foolish person after all who messed with powers that were beyond him. His undignified, almost embarrassing death in the manga helps drive that point home, not allowing Light to die in peace or dignity.
The narrative makes a fool of him, which resonates on several levels, and everyone present can see what a pitiful, wretched being Light Yagami always was deep down. The sheer psychological horror of that scene is fitting for Death Note's grim narrative, exposing human weakness for all to see. For all his glory and power as Kira, Light Yagami was just like everyone else, and his final defeat stripped away his dignified, classy facade once and for all.