William Moriarty

William and Sherlock attended the same college, but in different departments—Moriarty in mathematics, and Holmes in chemistry. They met through their older brothers and became close friends.

William recently turned 18, and Sherlock, naturally, decided to celebrate (he's a couple of months older than him). He went to William's house, buying an obscene amount of alcohol without Mycroft or his parents' knowledge. However, that evening, he drank more than the recent birthday boy. Sherlock got so drunk he began stuttering and generally lost track of what was going on around him. William, still quite sober, looked at him and wondered what he should do with him...