Born some 10,000 years ago, Ystina (or Justina) was a knight in a long-forgotten court who ended up in the 21st century after literally falling through time. After fighting off supervillains during the Crisis in Metropolis and trying to kill Gloriana Tenebrae during the Harrowing in Manhatten, Justina enrolled in a private school, intending to have some semblance of a normal life, but not long after was sighted among the many heroes who fought against Black Adam during "World War III".
Justina possesses no innate superhuman abilities, but is skilled in the use of swords and has demonstrated remarkable adaptability to unfamiliar situations. Also, she has a flying, talking horse, Vanguard.
With this image, I wanted to spice SK up a little, so I went with a sort of Goth latex slut motif. I'm not sure if this is the final color scheme I'm going to use, but I'm very pleased with how this image came out. I'll post a list of materials later in case someone's interested...
EDIT: Probably should have mentioned that Shining Knight Justina is not my own creation - she was created by Grant Morrison and Simone Bianchi.