Mark. My middle initial is C, and I'm a rapper and do presentations, thus I adopted the nickname Emcee (M.C.) after some kids and faculty in highschool started calling me that after I hosted some events. And an inside joke with friends led to M.C. also standing for Main Character, when some friends and I noticed that the Main Character in Persona 4 kind of looked like a younger me. So it's like a triple-meaning.
Some of my friends call me Emcee sometimes, but usually in a mocking way. But I'm at the point where much more people call me Emcee since I started my silly little web series under that name. Now most people I interact with call me by the nickname, or my username on this site, which is kind of surreal, since none of them even know where the nickname came from. Most probably don't even know my real name. I think my real name suits me somehow, in an impossible to describe way. I remember being annoyed as a little kid when people called me Marcus (IT'S NAWT MAH NAIME!!!1!!)
My username here is just an un-clever joke with no particular origin.