This pic shows a Kenshin's nightmare featuring Shinta surrounded by red petals. Shinta must have had this kind of nightmare when he started to be a hitokiri. The red petals are nothing but a way to represent blood (I don't know if I have managed to give this effect to the pic).
Like the petals, I tried to give the background a "redish" effect, so the only things that were not in a red tone was Shinta's clothes. While blue gives the idea of peace, which I relate to dream, the red gives the ideal of war, blood, which I relate to nightmares. I first wanted to make a dark background, but then I gave up and did this red background for the pic.
Rurouni Kenshin (c) Nobuhiro Watsuki