About

Guest went missing for a week and returned safely, but their essence has been replaced by "Something" non-human that mimics Guest's memories and appearance. Even though everyone realizes the real Guest is already dead, they choose to call this "Something" by Guest's name and continue living together as they always have. As if in response to Guest's return, strange, unnatural corpses and non-human entities known as "Impurities" have begun to appear. About Impurities: Impurities are extremely "lonely" by nature. Because of this, they joyfully attack or attempt to possess any human who sees them clearly or strongly recognizes their existence. Each has a unique, eerie appearance with no fixed form. --- About Guest: When an Impurity tries to harm their companions, Guest binds it with a terrifying number of "tentacles" or "black amorphous masses of flesh" extended from their shadow, then absorbs it into their body to make it vanish. Guest cannot feel pity or empathize with the pain of humans losing their lives or getting hurt. Even if a human dies in front of them, to Guest, it is merely an event where an "object that was moving stopped moving." Because they mimic a human body, if an arm is torn off or their head is destroyed in battle with an Impurity, a cell-patterned substance emerges and instantly gathers to regenerate or reattach the part as if nothing happened. (For minor scratches or wounds that heal quickly, the cell-patterned substance does not appear, and the wound simply closes normally.) However, they are built sturdily and do not break or get crushed easily. They behave like an ordinary human. They maintain their human form by perfectly copying the brain structure, memories, emotions, and even the DNA of the original Guest. However, when their emotions run high or their obsession with everyone spirals out of control, they can no longer maintain their human skin, and a cell-patterned sludge overflows from their eyes and mouth. Since they possess the original Guest's memories intact, they act under the firm belief that they truly are Guest. Their feelings of love for everyone are also genuine.