Light. Seventeen year old child prodigy, genius…perfect. Attractive, intelligent, polite, clever, respectful…he was everything a parent wanted in a son, a girl wanted in her lover, a person wanted in a friend…a detective wanted in a rival.

L. Twenty-four year old grown-up child prodigy, genius…far from perfect. He was one more cake away from diabetes, never seemed to sleep, seemingly apathetic, unkempt, socially awkward…he was everything expected of a mad genius, a prison convict perhaps, an untidy teenager…not a delusional serial killer's rival.

Growing up in Wammy's House, an orphanage for gifted children in the field of intellect, Lawliet read many detective stories, wanting to be a detective himself one day. His favorite series was Sherlock Holmes.
Growing up in his Japanese home with his parents and younger sister, Light Yagami read many detective stories, wanting to be chief of police like his father one day. His favorite series was Sherlock Holmes.

L, being sociopathic, had little care for most people, save for the fact that each life, in his opinion, should not be wasted in death. There were, of course, those few people that had managed to make their ways into his anti-social heart though.
Light, being highly functioning sociopathic, had little care for most people, save for the fact that each life, in his opinion, should not be wasted in criminal activity. There were, of course, those few people that had managed to make their ways into his falsely social heart though.

L was tracking down Kira to the best of his abilities whilst knowing not a name, nor a face, and having very little information to work with.
Light was tracking down L to the best of his abilities whilst knowing not a name, nor a face, and having very little information to work with.

Light was L's Moriarty. L was Light's Holmes. And just as Sir Arthur Conan Doyle had written, the final problem was to be closed in this final moment as Rem was writing a name in her Death Note. The difference was, Sherlock survived…L…did not.