Lumiya was Luke's object of special attention during the Galactic Civil War and a supposed Rebel. Turns out that she was actually an Emperor's Hand, trained by Vader, and a self-called Sith, though I don't think she is, though she is very powerful.
Luke flew into battle with Rogue Squadron in TIE fighters for confusion of the Imps, or something...and his systems went out so he tried to use the Force to pick his targets...he ended up shooting down Lumiya (aka Shira Brie) and she got messed up by that.