L is one of the most unique characters from Death Note. He is the world's greatest detective, solving many cases for years and taking action when he discovers that criminals all around the world are dying from heart attacks at the same time. He also has a lot of quirks and mannerisms that make a lot of fans like him. However, he's also failed in many ways throughout the franchise.
There have been many adaptations of Death Note over the years, with each of them changing some things about L. His biggest failures are spread out across the manga, anime, and live-action movies.
10 He Sent FBI Agents To Japan
When L first started investigating Kira, he learned that his opponent's first victim was from Japan, so he sent twelve FBI agents there. The FBI agents observed police officers and their families, with one of them, Raye Penber, watching Kira himself. After Kira found out about this, he found a way to kill Raye Penber, along with the other eleven FBI agents. Feeling responsible for this, L knew that this would be the most difficult case he'd ever been part of and that he'd finally have to reveal his identity to the members of the Japanese Task Force he could trust. That was something he never wanted to do.
9 He Let Light & Misa Out Of Confinement
After finding evidence that Misa was the Second Kira and becoming more suspicious that Light was the original Kira, L confined the two of them for nearly two months. During this time, Light set it up so that someone would take his place as Kira and kill criminals to make him and Misa look innocent. L refused to believe that Light and Misa were innocent, but the Task Force convinced him to end their confinement. Though he didn't want to, he understood that he had no choice. Luckily, he was able to keep an eye on them, but things would have been better for him if he kept them confined.
8 He Tested Aizawa's Loyalty
When the National Police Agency forced the Task Force to not go after Kira as officers, Aizawa, Matsuda, Mogi, and Soichiro had a difficult choice to make. They could've lost their jobs or kept investigating. The choice was especially difficult for Aizawa since he needed to take care of his family.
Long before this, L made sure his comrades would be taken care of financially if they were fired, but he wanted to see if Aizawa was loyal to him. Once Aizawa found out that L was testing him, he left the Task Force without any faith in the world's greatest detective.
7 He Should've Paid More Attention To Yotsuba
Because L was absolutely certain that Light and Misa were Kira and the Second Kira, he didn't investigate other suspects as thoroughly as he should have. He even overlooked the third Kira's connection to Yotsuba, a company that was benefitting from Kira's murders. In fact, he and Light both didn't realize that the killings that helped Yotsuba took place over the weekend until Soichiro pointed it out.
6 He Believed In The Rules Of The Death Note That Light Made Up
Before Light gave up ownership of the Death Note and let Yotsuba use it to their advantage, he wrote fake rules into it. When L and the Task Force found out about these rules, they believed them, though L was still suspicious of Light. One of these rules was that if someone who used the Death Note didn't continue to kill people, they would die thirteen days after the last name they wrote down. That made Light appear completely innocent. The other fake rule was that if the Death Note was destroyed, everyone who touched it would die. While L still believed Light was Kira, the Task Force completely trusted him, and there was nothing he could have done about it.
5 He Let Rem Know That He'd Go After Misa
When Rem and Misa were introduced, Light saw them as threats and wanted to get rid of them. Knowing that Rem loved Misa and would do anything to protect her, Light made sure Rem knew that L was suspicious of her being the Second Kira. This caused Rem to write down both L and Watari's names in the notebook. In less than a minute, all of Light's biggest threats were killed, including L.
4 He Didn't Choose A Successor
Light didn't know there was a whole group of orphans who were raised to become L's successors. However, L died before he got the chance to decide who would replace him. The two best candidates, Mello and Near, were offered to work together by Roger, the man who took care of them. However, Mello didn't want to work with Near and ended up leaving.
The two would eventually meet again as rivals who wanted to prove to each other that they were worthy of being the next L. Though Mello eventually helped Near catch Light, their rivalry also caused a lot of bad things to happen in the second half of the series.
3 He Was Too Reckless When Confronting Light
Though the anime version of L is the most popular among fans, there are other versions of him that are quite different. The biggest example was the Netflix adaptation's portrayal of the character, who was much more reckless when trying to prove that Light was Kira. While most versions of L did their best to be as mysterious as possible to hide their identity, L went on TV in order to challenge Kira. He also showed his face to Light when he didn't need to. If he had taken more precautions like the previous versions of his character had and didn't make so many foolish mistakes, he wouldn't have suffered throughout the movie as much as he did.
2 He Was Taken Off Of The Kira Investigation
At the end of the movie, L was removed from the Kira Investigation for multiple reasons. Thanks to his recklessness, he arguably caused more harm than good. On top of that, Light made himself seem innocent by being in a coma for two days while a criminal wrote names into the Death Note on his behalf. L had lost so much throughout the movie, from his sanity to his closest friend, and the last thing he needed was to lose to Light. When the second movie in this new series is released, it'll be interesting to see what L does next, especially now that he has a page from the Death Note.
1 He Had To Write His Own Name In The Death Note
Before the Netflix movie came out, there was another live-action film that was quite different from other adaptations of the series. L Change The World took place in an alternate reality where L defeated Light by writing his own name into the notebook after discovering it, giving him more time to live than he did in other adaptations. Though L was able to prove that Light was Kira and solve one last case during this time, it also meant that he was going to die no matter what happened.