"Orphaned at a young age, Naoto was found suffering from amnesia after the extremely violent murder of her parents, which also resulted in an iconic X-shaped scar across the middle of her chest. She was taken in, raised and trained by a swordsman whom she believed to be her parents' murderer. He named her Naoto after someone else in his own past, but never revealed his own name to her. After his subsequent murder she discovered that her parents were killed by an assassin whom she was named after; the original Naoto. Following his death she has uncovered the name of her mentor, Fuyumine, and adopted it as her family name. It seems that after the years spent with Fuyumine she developed some affection for him and even refers to him as "father" after his murder"
Took this from wikipedia
Original character made by Shirow Miwa ("Dogs: Bullets & Carnage")
Actually I've just coloured the page from manga.
Love this manga