Danny West was first introduced in the New 52 volume of the Flash during the title's Zero Issue, set five years prior to the first issue. When Daniel was born, his mother died, making his father William feeling hatred for the boy and becoming an alcoholic. Abusing his children, Daniel eventually came to a breaking point and he pushed his father down stairs, crippling him. Afraid of what Iris will think about him, he ran away, becoming a small time crook. Danny was seen driving a getaway car before being stopped by Flash and getting arrested. Danny would then have another encounter with Flash but with him this time being out of costume, in which Barry would help the police stop Danny from escaping the prison.
Danny would once again make an appearance five years later during the Gorilla City invasion of Central City. Danny, having gotten out of prison early on parole, tries to reach Iris West before getting attacked by a Gorilla soldier. Danny is then seen going to Iris' apartment to find her, yet finds that it has been vacant for days after looking at the mail. Daniel vows to find her. However, he was captured by Gorilla's and was rescued by the The Rogues who wanted to rob him. Daniel was able to escape by stealing Doctor Elias's monorail car which was powered by the Speed Force, giving him the ability to turn back the time.
Becoming Reverse Flash
Daniel took the name Reverse Flash, hunting down and killing everyone who has the connection with the Speed Force in order to absorb it into himself and gain enough power to travel through time and kill his father. When Barry find out the Reverse Flash can track down the speedsters and the reason why he still did not track down Barry is because his costume stops him from tracking him down, he gave one the Iris who at the time was also connected to the Speed Force.
When The Flash came to Doctor Elias' lab, he confronted the Reverse Flash and the two speedsters started a fight. Reverse Flash took one of Doctor Elias's weapons and when he tried to kill the the Flash with it, his sister Iris came to the scene when she took the blast in Flash's place. When Daniel find out that he actually killed his sister, he used his power to absorb Flash's speed and he started to go back in time to when he was eight years old and he killed his father. However, younger versions of himself and Iris saw Daniel, calling him a monster while looking at him with fear in their eyes. When he realized his mistake, Daniel gave up his powers and the Flash absorbed all of it, going back in time and fixing the time stream. Back in the present, Iris actually survived and Daniel told her that he does not regret trying to fix things between him and his sister. Daniel was sent back to the Iron Heights with Iris giving up on him.
Five years from the current DC timeline Barry Allen runs off to save innocents in Peshawar, Pakistan. While back in Central City Danny West is on the loose once again to cause mayhem which let up to a tragedy that resulted in Iris West's permanent disability and Wally West's death.
Twenty years in the future, Barry Allen traveled back in time to stop various tragedies he was not able stop in the past, one of which was Daniel escaping Iron Heights which led up to Wally's death. In the encounter future Flash makes Danny West realize the impact of his actions and his connection to the coming tragedy then later resolves to fix the situation by saving Iris and Wally from the eventual tragedy and killing Daniel by breaking his neck.
Powers and Abilities
Daniel gained the connection to the Speed Force by coming into contact with it's energy from Doctor Elias's battery, giving him the ability move time backwards and absorb the Speed Force from others. The more speed force his absorbed he becomes more powerful. His connection to the speed force and metal parts of monorail fusing with his body gave him enhanced strength and durability. Daniel can also project sharp metal projectiles from his body which also release electricity. Because of the monorail fusing with him, Daniel gained sharp claws on his fingertips. As every speed force conduit, Daniel is capable of unleashing large amounts of electricity from his body. Daniel also displayed the ability to tract down other speed force conduits in order to kill them and absorb their speed force energy. While he displayed the ability of time travel, it seems he no longer has the ability to preform those feats, or at least not without absorbing more speed force.