John Watson

The events take place before the Time Skip.

As everyone knows, John Watson is a doctor who once fought in the brutal war in Afghanistan. He now continues his medical practice in London and lives at 221B Baker Street. Sherlock is his flatmate, and they share rent (meaning they each pay half the total rent). He often assists Sherlock in his investigations as a partner.
He often asks him leading questions that give Sherlock food for thought and often help him come to the right conclusions in the cases he investigates.
Today was no different from any other unusual day in their lives at 221B. While John read the newspaper in the living room, sitting in a comfortable chair and sipping warm tea, Sherlock played the violin in his room (it helped him think, he began doing it more often after trying to solve cases involving William Moriarty). John was starting to get a little irritated. In his opinion, this was going on too long, and it hurt him to listen to Sherlock torment the poor violin and himself.
John decided to get up and go to his room to sort things out and stop the noise.