The Flash - Injustice: Gods Among Us: Arcade Ending: The Flash

A former member of both the Justice League and the One-Earth Regime, The Flash rebelled against his friends and allies, realising that they had become too focused on maintaining order at any cost, even the lives of innocent people. 

Defeating Superman and sending him to the Phantom Zone, The Flash helped dismantle the rest of the Regime, before going into a life of self-exile and permanently giving up the mantle of The Flash. 

Or so he thought. 

His desire to help others in need was too great, and, in the dead of night, he would use his superspeed to quickly take out criminals before vanishing again, so as not to let people see who he was. 

While some were able to piece together his identity from eyewitness accounts of a red blur, others would just be grateful that someone was looking out for them, dubbing him "The Ghost." Satisfied with the moniker, The Flash did not bother to correct them, choosing instead to take on the name and cast aside his old name and legacy, which had been forever tainted by the blood, pain, and fear of all the Regime's victims.