People? You've got to be kidding! You aren't human. You don't even have a human heart!
~ Shuuichiro Sakaki

Shuuichiro Sakaki is a major character in the visual novel and later anime Ookami Kakushi. Shuuichiro was a man living in born in the town of Jouga-machi, sometime in late 1950s. The town of Jouga, on the surface a normal town in the mountains, notable for growing hassaku fruit, and for tales of an endemic subspecies of wolves were said to inhabit the forests surrounding the town, the basis for a local goddess said said to take the form of a "white wolf". In truth, however, the "wolves" were actually a metaphor for the behavior of the local inhabitants, who are referred to as kamibito, and are said to "both human and not human". It is implied that they may be a different subspecies of humans. The main features of kamibito are an enhanced sense of smell, superhuman strength and agility, and an innate attraction to certain humans, known as "Temptations" who emit a pheromone undetectable to normal humans, but irresistible to the kamibito. When exposed to the pheromone, and particularly, if they come into contact with bodily fluids of an individual who emits said pheromones, (typically by kissing or sexual contact, as the kamibito will literally "fall in love" with the emitter) they become addicted and prone to insanity and violence.

It is revealed that Sakaki was in fact a powerful pheromone emitter or "tempatation", who fell in love with a kamibito girl named Mieko, who he was engaged to. However, Mieko's kissing and possibly having sexual contact with Shuuichiro was an offense under the ancient laws of Jouga intended to control the kamibito, and Mieko was assassinated by Nemuru Kushinada. Sakaki found Mieko dead in a pool of her own blood, and tried to report the crime to the local police, however, they were not at their posts, when he returned to the crime scene shortly afterwards, all evidence had been cleaned up.

Sakaki blamed the kamibito and the town of Jouga-machi as whole and spent two years plotting his revenge, intending to destroy all of the kamibito. Sakaki posed as a hitman, who was hired by the Jouga-machi leadership to eliminate another powerful "temptation", a boy named Hiroshi Kuzumi. Shuuichiro kidnapped Hiroshi and held him at a construction site, which had the unintended consequence of attracting Nemuru Kushinada to the site. Sakaki and Nemuru fought, with Sakaki managing to disable Nemuru in spite of her superhuman powers by cause debris to fall on her. Sakaki then held Nemuru in the same room as Hiroshi, intending to trigger her violent nature and cause her to kill him before he killed Nemuru.

Nemuru, however, resists the urge to make contact with Hiroshi and the two of them are rescued.Sakaki, however, escapes, and puts into motion a plot to cause chaos by releasing a "fallen" into the Hassaku Festival, where all the town would be attending, forcing Nemuru to kill the "fallen" in order to protect the rest of the town, revealing the murderous secrets of Jouga. In the chaos that ensues, Sakaki murders one of the town leaders with a switchblade, before he escapes, and heads for a dam upstream, armed with a switchblade and a revolver. Sakaki shoots one of the dam personnel and proceeds to open the floodgates, intending to flood Jouga and wipe out the entire town. The flooding causes some damage, but Nemuru and several other townspeople follow Sakaki and manage to close the floodgates before most of the town is destroyed.

Nemuru then confronts Sakaki on the other side of the dam, who points his pistol at the group. In the anime, Nemuru admits to killing Sakaki's girlfriend, and offers to allow him to kill her if he would spare the lives of the rest of the town. Sakaki does not take the offer, and attempts return the dam, pointing the gun at anyone who would stop him. However, he is met by, Kaori Mana a girl who was his friend in college, who is actually a kamibito, who tries to stop him. Sakaki shoots Kaori, but with her last breath, she jumps off the cliff next to the dam, pulling Sakaki along with her.

In the visual novel, Sakaki's methods of attempting to destroy Jouga-machi are somewhat different, using a large bomb to completely destroy the city, and, if he fails in that, inciting the human members of the town into murdering the kamibito. In some bad ends of the visual novel, he actually succeeds in his attempts to bomb the city.