Tokyo Ghoul by Sui Ishida

I've been getting requests for this title from my anime club for months, so I was thrilled when I spotted it in amongst the new books at work.

College student Kaneki's first date is a nightmare; the girl was a ghoul and tried to eat him. When Kaneki wakes up in the hospital afterwards, an organ transplant from his date has turned him into a human-ghoul hybrid and left him craving human flesh. Kaneki could be the key to helping ghouls and humans stop trying to destroy and start understanding each other. If he can just avoid being killed by another ghoul or a government agent, or going crazy with hunger and eating his friends.

Tokyo Ghoul is dark, gruesome, and perfect for horror fans. There are plenty of vicious fight scenes, but interspersed with quieter moments where Kaneki battles his new instincts or tries to figure out how to survive in this new, dangerous world he's stumbled into.  Not for the faint of heart, but well worth reading. Rated for older teens.