A little at a time, creator Sui Ishida draws the reader into a whole new world, with its own biology, its own technology and its own culture. And as in the best manga, he tweaks the rules as he goes along, keeping the story fresh and the reader guessing.
The ghouls of "Tokyo Ghoul" are different from the ones found in folk tales. Old-school ghouls look like monsters, live in graveyards, and dig up corpses or shapeshift into animals to lure the living into lonely places for the kill. Tokyo ghouls, on the other hand, are urban sophisticates who hang out at a local coffeehouse, Anteiku. Even hipster ghouls must eat human flesh to live, however. They can't digest human food, and in fact find it repulsive -- except for coffee, which allows them to find common ground with their human neighbors at Anteiku.
Of necessity, then, ghouls and humans are enemies. The survival of one depends on the death of another -- either the ghouls must eat the humans or the humans must kill the ghouls. So what happens if you have some of each in you?
That brings us to "Tokyo Ghoul's" main character: Nebbishy human Ken Kaneki, a dreamy, bookish guy who receives an organ transplant from a ghoul and is left half-human, half-ghoul - or, as he puts it, "I'd say my soul is human and my body's a ghoul."
Stuck with a ghoul's physical needs but a human's repulsion for fulfilling them, Ken seems to be all alone at first. However, it turns out that Anteiku is run by a particularly enlightened group of ghouls who want to figure out a way to coexist with humans. The manager, the fatherly Mr. Yoshimura, sees Ken as a possible bridge to the human world, and he not only gives him a job but offers to supply him with humanely sourced food. When Ken demurs, Mr. Yoshimura gives him a mysterious sugar cube that can quell his hunger for a little while, but sooner or later, the others warn him, he will have to accept what he is.
Ken's counterpoint is the badass ghoul Touka, who works alongside him as a waitress. If Ken is a human slowly transitioning to ghoulhood, Touka is the opposite: She appears cold and angry at first, but she is also reaching out toward the human world, going to a human school and trying to appear normal to her human friend. Although she feigns a disinterested attitude at times, Touka has a keen sense of justice and not only tries to keep ghouls from taking over each others' hunting grounds but also avenges the deaths of her fellow ghouls. As one expects of a female second lead in a manga like this, she's a hell of a fighter and racks up a number of kills in the first few volumes -- but sometimes she holds back.
Rounding out the beginning of the series are Ken's brash friend Hide, a young man of great enthusiasms and strong intuition; the widow Ryoko, whose husband was killed by ghoul investigators, and her young daughter Hinami; and the stolid Yomo, who takes care of business and watches over Ken and Touka.
The first arc of the series, volumes 1-3, is all about Ken coming to terms with the paradox of needing to eat human flesh to survive while still having human emotions, including not just revulsion for cannibalism but also the desire for friendship and emotional ties. That's not the end of his problems, however: The ghouls have their own predators, the state anti-ghoul squad known as the CCG. Ghouls have no human rights, and the anti-ghoul investigators -- known, ironically, as Doves -- often take sadistic pleasure in killing their prey. The chief ghoul investigators in this arc are the bizarre, almost corpse-like, Mado, who's obsessed with killing ghouls and converting their fighting organs into weapons, and Amon, a strait-laced, dedicated investigator.