L's successor

L's successor is the person who would succeed L if anything should happen to him.

Overview
"L" is known to all as the world's greatest detective, and his opinion is highly valued by world government officials. His status allows him to mobilize law enforcement whenever he needs them.

L remains hidden and communicates with the outside world via computer. He uses an electronic voice synthesizer to cover his voice, and his real name and appearance are currently unknown by the public.

Due to the dangers that come with being a world-renowned detective, L's life is assumed to be at risk. If anything should happen to L, L's successor will assume the position as the greatest detective in the world.

Becoming a Successor
Little is known about how one is chosen as a successor, though it seems that L himself chooses. The child is assumed to be selected from the residents at Wammy's House, an orphanage created by L's mentor, Quillish Wammy, also known as "Watari."

Manga / Anime
L has two successors, Near and Mello. It appears they were chosen at a young age, with Near being thirteen and Mello close to fifteen when they were introduced into the story. Of the two children, only one was intended to gain the title of "L," but because of L's death, neither child was officially selected. After learning of L's death, Roger Ruvie proposed to the two that they work together. Near agreed, but Mello found it impossible to work with Near and gave Near the position as "L."

The Current "L"
As shown in the manga one-shot taking place three years after the main storyline, Near remains the current L and solves cases under the L name.

Film Series
In the movies, L manages to catch Kira by writing his own name in the Death Note, though it still causes his death. In the 23-day period he has between writing his name and dying, he obtains a successor in alternate and obscure ways.

L: Change the WorLd
A Thai boy rescued from a virus-destroyed village who spends the duration of the film with L and Maki Nikaido is named "Near" while being taken to Wammy's House just prior to L's death.

Death Note: New Generation
In the film series sequels, Near's face is never seen. L's true successor is Ryuzaki, who claims to be "L's backup born from IVF," suggesting that he was created from L's DNA. There is a shot of him as a child with L, sharing some similarities with the nameless Thai boy from L: Change the WorLd.

Death Note: Another Note
The novel Death Note: Another Note greatly expands on information regarding L's successors. Within the novel, two other potential successors are introduced: A and B. These two are referred to as the "first generation" of successors, having been chosen before Near and Mello. The first successor, A, is unable to cope with the pressure of having to succeed L and commits suicide. The second, B, becomes a serial killer and later dies of a mysterious heart attack while in prison, presumably by Light Yagami or another owner of a Death Note.

L: Change the WorLd
Different from the film version, the book includes Near as he is portrayed in the manga, but the nameless Thai boy from the film is not present.