According to her father West, East was born very weak and as a result, in an attempt to save her life, West gave her over to Starlight Laboratories as a child, which led to a contentious relationship between the father and daughter. While Starlight was able to save her life with experimental treatment, she developed a speed-enhancing ability known as Burst Step as a side effect of the treatment. However East is actually a echo which is why she sometimes glitches.