The Kagerou Daze (カゲロウデイズ Kagerō Deizu, lit. "Heat Haze Daze"), also known as simply the Kagerou or the Daze, is a never-ending repeating world created by Azami that swallows up anybody who ends up dying on August 15.
- The Kagerou Daze is a never-ending world created by Azami, who was convinced by the Snake of Clearing Eyes to make it. Azami originally intended to live in this world with her family due to the fact that humans age much faster than her, she would've outlived her husband Tsukihiko, who was human, and their daughter, Shion. Tsukihiko wanted them to have a traditional wedding, so he went back to his village to get a wedding dress, but he was detained and beaten by the villagers about Azami. While waiting for Tsukihiko to come back, Azami and Shion are attacked by villagers. Azami retaliated by using her abilities and killed all but one, and used Stealing Eyes on him and saw what happened to Tsukihiko, and she decided to enter into the Kagerou Daze alone to not cause any more suffering to him and Shion. This world was revealed to be terrible, and Azami had been tricked by the Snake of Clearing Eyes.
- As time passed, her daughter, Shion, as well as her granddaughter, Marry, were murdered by humans and Azami ordered the Kagerou Daze to swallow them up, resulting in the Kagerou swallowing anyone dying on August 15th. Wishing for at least her granddaughter to live, Azami gave her the "Queen of the Snakes", also known as the Snake of Combining Eyes, which would serve as a surrogate life for Marry, while Shion remained.
- Azami lost her ability to unite the snakes because of this, so she was unable to undo the order she gave to the Kagerou Daze: "Bring in the people who died on August 15 (the day of Shion and Marry's deaths)". To enter the Kagerou Daze, a living creature must die on August 15th. It's possible for one of the snakes to possesses someone swallowed into the Kagerou, acting as a surrogate life and giving them an eye ability, which also makes it possible for them to leave the Kagerou, while others don't and remain inside the Kagerou Daze.
- Azami is able to trap the Snake of Clearing Eyes in the Kagerou Daze by regaining control of 5 of her 10 snakes in the novel but is unable to defeat him, resulting in Marry rewinding time again.
|Involved||Cause of Death||Image|
|One day, her father's business went bankrupt, leading him to murder his wife and trap his eldest daughter, Rin, in his mansion and set it on fire. While he did not intend for Tsubomi to die, she refused to leave her sister in the burning mansion, and so they both died in the flames and came in contact with the Kagerou Daze.      |
|On a stormy day during his childhood, Seto witnessed some children trying to throw his only friend, a dog named Hanako, into a river. Despite his efforts, the dog was thrown in and Seto jumped into the river in order to save it. They both ended up drowning.     |
|During his childhood, Kano came home to his apartment and found the door unlocked. Thinking that his mother was home, Kano went inside only to find his mother tied up and two men taking her jewelry. Knowing his mother worked hard to get the jewelry, Kano tried to take the jewelry back but was overpowered by the men. When they were about to kill him with a knife, his mother took the blow. Shaken, Kano continued to resist the men and was thereupon stabbed.      |
|Despite her mother's warnings, Marry went outside her home for the first time and was found by two humans and almost kidnapped. Shion found her in time to turn one of the attackers into stone, but the strain of her ability caused her to collapse. The remaining human then killed Marry and Shion with a blunt object.   |
|Momo was visiting the beach with her father when she got caught by the waves and drowned, resulting in her death. Her father drowned with her in an attempt to save her.   |
|Takane Enomoto||During high school, she lost her life when someone administered her with a drug. Through a window in the dark, she was able to spot her teacher Kenjirou, who did not only have her body connected to an unusual machine, but also Konoha's, who was placed in a tank of some kind. Before being able to figure out why Haruka's video game character lived, she touched the window by accident and began to disappear. In Manga Route 2, Takane commits suicide after learning of Haruka's death.     |
|Shintaro Kisaragi||Route XX: Instead of meeting the Mekakushi Dan, Shintaro remained at home, grieving over the loss of Ayano, Haruka, and Takane. Ene begged him to bring himself out of his sorrow and go outside, but Shintaro refused to listen to her. Eventually, he became angry and annoyed with her, which led him to get rid of her. After this, Shintaro fell into greater despair and committed suicide by slitting his throat with a pair of scissors.
Route 1: While the Dan is confronting the Snake of Clearing Eyes, who has taken over Konoha's body, Konoha temporarily regains control of his body, and uses the chance to point a gun at his own head. Shintaro rushes to stop his friend from killing himself, but is too late to stop the trigger from being pulled. He moved Konoha's arm enough that the bullet's trajectory is changed, hitting Shintaro's head instead of Konoha's. 
|Hibiya and Hiyori got caught in a traffic accident during summer and were both swallowed into the Kagerou Daze. In the Novel Route, they end up in the middle of a traffic road after being attracted there by a black cat, who is revealed to be Kano. In the anime route, the Snake of Clearing Eyes arranges it so that the two of them are kidnapped with the intention of killing them. They escape, but end up killed by a truck anyway.     |
|Haruka Kokonose||In his second year of high school, he suffered a sudden attack from his illness and lost his life. In the Kagerou Daze, he met Azami and was presented with a new body: the body of his video game character, Konoha. Haruka denied the body and was forced to stay in the Kagerou Daze as a result, while the Snake of Awakening Eyes possessed his empty body and left to the real world as Konoha.      |
Ayano Tateyama (Manga Route 2)
|Kenjirou was on a field trip with his wife, Ayaka, to study the Medusa and her abilities when they were caught in a landslide and lost their lives. In Manga Route 2, their daughter, Ayano, died in the landslide with them and entered the Daze alone.     |
|Ayano Tateyama||After her mother's death, Ayano discovered that the "Legend of the Medusa" is not just a tale but a real phenomenon, and that her father was possessed by one of the snakes. She soon found that the snake was following her father's wish to see her mother again and planned to return all the snakes in the Daze to the real world with a new Medusa, which would result in the deaths of her adopted siblings and friends at school. She attempted to cut their plan short by jumping off her school's rooftop and entering the Kagerou Daze, where she would gain her own snake and stay there.    |
- According to Haruka, the Kagerou Daze creates the scenery for its inhabitants. The scenery is a reflection of what is in someone's heart and mind. He also notes that the Kagerou Daze tends to depict people as they picture themselves, no matter how they actually look.
- Kano's Daze is a town during nighttime. The sky is described as inky black, with only the moon standing out.
- Haruka's Daze is an operating room. In the room, there are a vast, almost uncountable number of IV drips, strewn all across a pure white space. The IV drips are each linked to a separate bag filled with a colorless liquid. The other ends are all connected to a single bed with white sheets. The smell of a hospital seems to hang around in this room.
- Ayano's Daze is a wooden school classroom drenched in the light of the sunset. It's filled like any old classroom with things like desks, seats, windows to the side with curtains, etc. On the other side of the windows, one can see a darkened city.
- Takane's Daze is a collapsing city that she has to escape from.
- Shintaro's Daze is the road he took to and from high school.
- The locations where each character is shown for the first time in the anime are the locations of their individual deaths, excluding Marry.
- Kido named the world.