Barry Allen was a boy when his mother was murdered and his father was wrongfully convicted for it. He would spend most of his life trying to prove his father's innocence and believes in justice. He would become a forensic scientist for the Central City Police Department. During an electric storm he was working in his lab and a bolt of lightning struck him while shattering chemicals. The electricfied chemicals spilled on him. This is the accident that gave Barry his super speed. He decided to help humanity and fight crime as The Flash.
The Flash is mostly known for just running really fast but he can do more than just that. The Flash is very creative with how he uses his speed. Also evrything about him is fast including his metabolism. His speech, reading, and thinking can also be faster than the spped of light.
Speed Force power: The Flash created the speed force which is what gives speedsters their power. The speed force barrier is the last barrier and basically the fastest you can go. Beating the sound Barrier, light barrier, time barrier, dimensional barrier, and then the Speed force barrier. Every step he takes he generates the speed force.
Accelerated healing: speedsters heal at extreme speeds
Decelerated Aging: Speed Force slows speedsters aging
Energy Construction Creation: speedsters can use matter generated by their speed to create solid object like walls or bridges, after-images are the same thing.
Flight: only by moving their arms at high speeds like a helicopter or running fast enough to be launched at high speeds but are faster on their feet
Increased Perception: traveling fast they might miss events so the speed force gives them enhanced senses
Infinite Mass Punch: generating enough speed to use all that momentum into one massive punch able to push metahuman onto another continent. Also he can punch someone 1 billions time per second.
Phasing: vibrating their molecules at high speeds making them able to phase through objects
Self-Sustenance: burning calories so much that the need to refill their energy supply. So they can eat probably 160 tacos and still be at top fit condition due to them using up lots of energy.
Speed Force Aura: a protective aura from the speed force able to survive in harsh conditions
Steal Speed: can basically steal speed from any fast moving person
Super Speed: able to reach speeds faster than the speed of light but if tehy go too fast or don't realize it they will become apart of the speed force
Vortex Creation: speedsters can create tornadoes by turning their bodies or rotating their arms to create powerful gusts of wind
Super speed brain activity: able to operate at superhuman speeds. Test thousands of theories, understand impossible equations and run trial and error in their brains within a matter of mintues or even seconds.