Moriarty, the organization, was, still is in fact, Sebastian Moran's job. It wasn't the healthiest of jobs, he killed people. The pay was good though and for a person with zero ethics, like Sebastian, it was a good job.

Nevertheless, Jim Moriarty, the psychotic man, was the one who pulled Sebastian out of the gutter, literally.

After being dishonorably discharge Sebastian had nothing, no parents, and no siblings to go to. Having no money and barely any possessions Sebastian was living on the street the moment he got back to England. With little liquid of any kind and almost zero food he was a starving cat in the sewers. But, when Jim found him, he made him back into the deadly tiger he had been before, when he was in the army.

For that, Sebastian was thankful. He would've died if it wasn't for Jim.

And in the end, Jim became his world. Every command he followed through with, every order made perfect. Never did he disappoint Jim.

Because of this, it didn't surprise anyone that he eventually fell in love with Jim. Sebastian's few contacts that he visited frequently thought it was obvious. Obvious to everyone but Jim that is. Sebastian left hints, tried to place ideas in Jim's mind but despite being such a genius he never did get it.

Sebastian could live with that though. As long as he was able to work with him it was fine but then came that call. The call that explained the consulting criminal's true plan.

And when he said, "This is good bye Sebby," Sebastian broke into a run. His old tennis shoes hit the pavement as his hair became plastered to his face from the sweat that ran down his body. When he got to the building, he could be crowded around the front, looking up, looking at Sherlock.

That right there should've been a dead giveaway but Sebastian kept running. He ran inside, taking the elevator because a small part of his mind new that it didn't matter because it was already to late.

He banged his head and hands against the walls that enclosed him as the elevator went up and up. Finally, he made it to the roof, a few tears already mixing with his sweat.

And there lay Jim, dead.

Sebastian fell to his knees, not able to, not wanting to move. He felt more broken than ever before, absolutely destroyed in fact. For days after that he sat in his flat feeling like a shell of what he use to be just because he had had the misfortune of falling in love with the most dangerous man in London, no the world.

Then the letter came. A letter from Jim instructing Sebastian what to do from beyond the grave. He was the head of the organization now. Sebastian didn't want to be, he wanted to stay Jim's right hand man but he also didn't want to disappoint Jim.

He became the head of the organization, and in some ways, was even more ruthless than his predecessor.

All because he had loved.