Tokyo Ghoul

=== Setting ===
Tokyo Ghoul is set in an alternate reality where ghouls, creatures that look like normal people but can only survive by eating human flesh, live among the human population in secrecy, hiding their true nature in order to evade pursuit from the authorities. Ghouls have powers including enhanced strength, speed, endurance and regenerative abilities—a regular ghoul produces 4–7 times more kinetic energy in their muscles than a normal human; they also have several times the RC cells, a cell that flows like blood and can become solid instantly. A ghoul's skin is resistant to ordinary piercing weapons, and it has at least one special predatory organ called a Kagune (赫子), which it can manifest and use as a weapon during combat. Another distinctive trait of ghouls is that when they are excited or hungry, the color of their sclera in both eyes turns black and their irises red. This mutation is known as kakugan (赫眼; 'red eye').
A half-ghoul can either be born naturally as a ghoul and a human's offspring, or artificially created by transplanting some ghoul organs into a human. In both cases, a half-ghoul is usually much stronger than a pure-blood ghoul. In the case of a half-ghoul, only one of the eyes undergoes the "red eye" transformation. Natural born half-ghouls are very rare, and creating half-ghouls artificially initially has a low success rate. There is also the case of half-humans, hybrids of ghouls and humans that can feed like normal humans and lack a Kagune while possessing enhanced abilities, like increased reaction speeds, but shortened lifespans. Naturally born half-ghouls can also eat like normal humans or full ghouls.

Plot

The story follows Ken Kaneki, an 18-year old university student who barely survives a deadly encounter with Rize Kamishiro (his date who reveals herself as a ghoul and tries to eat him) when she gets hit by falling construction girders. He is taken to the hospital in critical condition. After recovering, Kaneki discovers that he underwent a surgery that transformed him into a half-ghoul. This was accomplished because some of Rize's organs were transferred into his body, and now, like normal ghouls, he must consume human flesh to survive. Ghouls who run a coffee shop called "Anteiku" (あんていく) take him in and teach him to deal with his new life as a half-ghoul. Some of his daily struggles include fitting into the ghoul society, as well as keeping his identity hidden from his human companions, especially from his best friend, Hideyoshi Nagachika.
The prequel series Tokyo Ghoul [Jack] follows the youths of Kishō Arima and Taishi Fura, two characters from the main series who become acquainted when they join forces to investigate the death of Taishi's friend at the hands of a ghoul, leading to Taishi eventually following Arima's path and joining the CCG (Commission of Counter Ghoul), the federal agency tasked into dealing with crimes related to ghouls as well.
The sequel series Tokyo Ghoul:re follows an amnesiac Kaneki under the new identity of Haise Sasaki (the result of horrific brain damage sustained from Kishō Arima). He is the mentor of a special team of CCG investigators called "Quinx Squad" that underwent a similar procedure to his, allowing them to obtain the special abilities of Ghouls in order to fight them but still being able to live as normal humans.