Sebastian Moran: http://en.wikipedia.org/wiki/Sebastian_Moran

Moriarty's second in command and "the only of Moriarty's henchman with absolutely unwavering faith in Moriarty." Also referred to by Holmes as "the second most dangerous man in London." Read up on him as he may very well be sneaking up on us for next season.

The counterpoint to that is the statement "But a man named Moran was arrested in Empty Hearse!"

Yes, he was. As part of a terrorist plot. "A Scandal in Belgravia" shows us Moriarty was involved with terrorists, specifically the ones intending to blow up the flight that would be known as "Bond Air." The original Moran was an officer in the English Army, a government position, before joining Moriarty. The TV shows Lord Moran (first name not given) also held a government position.

Or the name Moran was just a nod to fans of the Doyle canon and we'll never see him again. I don't know!