The Greek interpreter

Here comes Mycroft at least!

On a quiet day, while chatting about heredity, an astonished Watson learns that Sherlock does have a brother! Having never heard of a family, he had pictured him alone and orphan... Without any further delay, Sherlock takes him to the very discreet Diogene's club.

Mycroft Holmes

Mark Gatiss reserved a choice character for himself, and he did well to do so! His Mycroft is puzzling, subtle, cold and annoying, but sometimes lovable when he accepts to show that he cares for his "little brother".