Was the Tokyo Ghoul OP made before the Anime or specifically for the anime? Was the song Unravel (OST Tokyo Ghoul) made specifically for the Anime, or was it already made before the Anime, and was just used by the studio for the Anime. If it predates the Anime, was it as famous as it is now, or did it gain popularity after it appeared in the Anime ?
I do not know if it was made specifically for the Anime, but the Anime was the debut of the song. The first episode of the Anime having aired on July 4th, 2014 and the single containing the song being released on july 23rd, 2014.