I wouldn't even think he was cosplaying, but it seems the mark on his chest is pretty significant. I have no idea what it means, and I'm not familiar with any anime or manga associated with it.
Thoughts anyone?
EDIT: Thanks to everyone who commented to let me know this is Kanda Yu from D. Gray-man! I only wish people would leave their names next time. ^^; And also thanks to Izzy for letting me know the cosplayer is known as Miyoc.
