Sinister, Dexter (слэш)

"Sherlock hates not knowing things. What is merely an inconvenience to most people is, to him, a cruel twist of fate. When he is nine, he bribes Mycroft to hack into the police database and read the files on John Watson and Jim Moriarty."
Everyone is born with a name on either hand - one is their soul mate, and one is their archenemy. Sherlock is born with Jim and John on his hands, and must decide which is which.