Kid Flash (Bart Allen)Created by Mark Waid & Mike Wieringo (The Flash #92)
Bart Allen was the son of Don Allen of the Tornado Twins and Meloni Thawne, a descendent of Professor Zoom. When Bart was born, his connection to the Speed Force caused him to age at a rapid rate, so he was raised in virtual reality until he had to flee with his grandmother Iris West back to the 21st century.
Wally West was able to cure Bart of his condition, but an entire life spent in a simulation caused Bart to have no concept of danger, which meant he would rush into situations without considering the consequences. This garnered him the superhero codename Impulse, and he frequently clashed with Wally West, who was ostensibly his mentor, though that role was filled much better later on by Max Mercury.
Following Max’s death at the hands of The Rival, Bart went to live with Jay and Joan Garrick and joined the new incarnation of the Teen Titans as Kid Flash. During the events of Infinite Crisis, the Flashes trapped Superboy Prime in the Speed Force, but when he escaped Bart was sent out after him and came back several years older as the new Flash, a role that was short lived as his evil doppelganger Intertia manipulated The Rogues into killing him.
Bart was resurrected by Brainiac 5 of the Legion of Super-Heroes and returned to combat the Legion of Super Villains before returning to his home time. During the Flashpoint, Bart merged with the Speed Force and became the White Flash in order to give his uncle the speed necessary to fix the timeline.
Also important to note, as Bart Allen is my favorite character; the Bart Allen that showed up in The New 52 was actually a war criminal named Bar-Torr hiding out in the past under an assumed name. Presumably Bart Allen is still in the Speed Force and can return some day, just as Wally West has, but there are a lot Kid Flashes at the moment.