The nove tag (character from Mahou Shoujo Lyrical Nanoha StrikerS) is currently highlighted as an artist tag in red, instead of the usual green character highlight.
Updated by kittey
Try asking the user Xeano94, who added the tag to post #1140782, which’s source is listed in the artist profile.
My guess would be that it was a mistake.
Edit: Seems to have been fixed by now.