I have had this name since I had time with the PS2 and Xbox and had to create a username.
The original names were SergioT101 and T102 (for Halo 1 and 2 respecively)
the name Sergio came from the footballer Paulo Sergio, who played for Brazil and A.S Roma at the time. the second name was just used because of the first name in my own.
and of course, T101 and 102 came from the terminator series for the model T-800/Model 101.
Anyway Sergio worked well, until as a joke while playing Red Raction 2 with one of my friends I made Sergio Mach 3. This was due to the new wave of Gilette mach 3 blades that were in shops at the time and was a pretty funny to add the number 3 in (as opposed to Sergio 3 which didn't flow well saying it).
You can thank these
Maybe for the next generation I will add in Mach 6, but for now it will do.
So yeah that's the gritty origins story.