Tracer

Tracer is an Offense hero in Overwatch.

Summary
With a unique ability to control the speed of her own passage through time, Tracer zips and blinks around the battlefield, eluding attackers and sneaking past defenses. A perfect skirmisher hero, Tracer is fragile but hard to hit, keeping one step ahead of her attackers while she harasses and harries the enemy team. Tracer excels at getting behind enemy lines, but it is inadvisable to move her through chokepoints.[3] Should she find herself blinking into an ambush, she can rewind time to her position and state a few seconds earlier, giving her a second chance.

The developers consider Tracer to have one of the most unique play styles in Overwatch.[4]

Story
Lena Oxton (call sign: "Tracer") was the youngest person ever inducted into Overwatch's experimental flight program. Known for her fearless piloting skills, she was handpicked to test the prototype of a teleporting fighter, the Slipstream. But during its first flight, the aircraft's teleportation matrix malfunctioned, and it disappeared. Lena was presumed dead.

She reappeared months later, but her ordeal had greatly changed her: her molecules had been desynchronized from the flow of time. Suffering from "chronal disassociation," she was a living ghost, disappearing for hours and days at a time. Even for the brief moments she was present, she was unable to maintain physical form.[6] Sometimes she had strange dreams about the past, including being a kitchen maid at a large house in the country.[8]

Overwatch's doctors and scientists were stumped, and Tracer's case seemed hopeless until a scientist named Winston designed the chronal accelerator, a device capable of keeping Tracer anchored in the present. In addition, it gave Tracer the ability to control her own time, allowing her to speed it up and slow it down at will. With her newfound skills, she became one of Overwatch's most effective agents.[6] At some point she was stationed at Watchpoint: Gibraltar.[10]