19. He's Killed
Not many heroes kill, and in the case of Barry Allen, it was thought to be an accident. Either way, this was a significant moment in the character's history. After the Reverse-Flash murdered Iris West in a fit of jealousy, The Flash's life fell apart. He would later meet someone else though, but the villain returned again to kill Barry's bride on their wedding day. This time The Flash was prepared however, but in the process of stopping his greatest foe, he snapped his neck. Despite everything the Reverse-Flash had done, Barry was left shaken up by the incident, and this was a dark time in the Scarlet Speedster's history.