The Mist is a supernatural force controlled by the goddess Hecate that twists a mortal's sight from seeing monsters, gods, Titans, and other supernatural occurrences by replacing them with things the mortal mind knows about and can comprehend. Some mortals can see through the Mist as well, including Rachel Elizabeth Dare, May Castellan and Sally Jackson. Demigods and mythical creatures can all see through the Mist at most times, though sometimes the Mist is strong enough to fool even demigods.
It is Hecate's job to make sure the mythological events are replaced with visions of normality. Under the influence of Mist, a mortal would see gods or monsters as ordinary humans or animals and supernatural objects become commonplace items. The Mist cannot only distort vision, but also creates false memories and suppresses real ones.
In the short story Son of Magic in The Demigod Diaries, the Mist is shown to be able to form into physical objects by Hecate and her children. Lamia distorted the vision of humans enough that they don't even realize that hazardous and deadly things are happening to them. Dr. Claymore's friend, Burly Black, burned to death without realizing a thing. Alabaster C. Torrington created an Imperial Gold sword and a guardian from Mist. Hecate created a Mistform body for the soul of Howard Claymore, who died to protect Alabaster.
The Mist is mentioned several times, normally hiding Percy's sword from mortal eyes by making it appear as a rifle or a baseball bat. It also hides monsters, such as when the Furies attacked Percy and his friends on a bus, but the people only saw Percy attacking three old ladies. The Mist also hides most of Percy's fight with the god Ares, making their swords appear as guns to the police and also hiding Ares' appearance as a god. The Mist also hides Camp Half-Blood from the eyes of humans, as anything inside the Camp Borders appear as nothing more than a strawberry field and the protective borders of the camp will prevent people from entering the camp.
The Mist made a group of Laistrygonians appear as normal students who were tall and scary until they showed their true form when they attacked Percy. The Mist also hid the fact that Tyson was a Cyclops until Percy looked directly at him. Later when given a quest into the Sea of Monsters, it is explained that there is a strong layer of Mist in the Bermuda Triangle, resulting in ships and planes getting lost inside it. Chiron later uses the Mist to make up a fake cover story to shift the blame away from Percy for the attack on the gym.
Thalia Grace showed that she is able to manipulate the Mist, as shown when she snapped her fingers and a teacher thought they went to the school but will Percy be able to do it or just envy her. Later, as the group climbed up Mount Othrys, Thalia explained that the top of the mountain had a very strong layer of mist. Percy then asked if she meant the magical kind or the natural kind, she explained that both forms were strong. This may also indicate the strength of the Mist in California due to the existence of Camp Jupiter in the vicinity (particularly San Francisco).
The Mist is very strong inside the Labyrinth. It is strong enough to fool demigods into traps or to get them lost. Percy eventually had to ask Rachel Elizabeth Dare for help, as she was a clear sighted mortal and could see through the Mist in the maze.
In The Stolen Chariot a mortal child can see the horses that pull Ares' War Chariot. It is possible that she can see though the Mist. In The Sword of Hades, the Mist makes Mrs. O'Leary look like a poodle, yet satyrs and centaurs must disguise themselves as opposed to going around as it is.
The Mist hid Typhon's true form from the eyes of demigods and humans. Regular humans saw it as a freak storm system that was moving across the country toward New York City, although demigods such as Percy Jackson could see part of his form. However, Percy claims that he could have been driven crazy if he looked at Typhon for too long.
The Mist causes many false memories of Jason Grace with Piper McLean and Leo Valdez. However, their false friendship becomes a reality, with Piper's love interest with Jason eventually becoming true. It is also revealed how the gods used the Mist to divide the two camps.
On the bequest of Hecate, goddess of the Mist, Hazel Levesque learns to manipulate the Mist in order to confront the sorceress Pasiphaë and the Gigante Clytius. She also uses her abilities with the Mist to manipulate the demigod Sciron.
Hazel uses the Mist to bend the Labyrinth to her will, making passages appear and tricking Pasiphae, making her believe that she fell into a chasm.
Unlike in the series, where the Mist will blind mortals to anything relating to magic, the gods, or monsters, the Mist can be applied using a magical "spraying" object. However, the Mist itself does exist without the spray, which is shown when the gang visits the coffee shop and the mortals see the man at the kiosk with only two hands instead of eight.
Humans With Clear Sight
- Marie Levesque
- Maria di Angelo
- May Castellan
- Sally Jackson
- Frederick Chase
- Dr. Howard Claymore
- Amir Fadlan
- Rachel Elizabeth Dare
- Some mortal children can see through the Mist, as they are more open minded and have a much more vast imagination.
- Several Los Angeles gang members in The Lightning Thief were able to see Riptide as a sword.
- The Mist doesn't completely hide some of the physical features of Satyrs/Fauns, leading them to find numerous ways to disguise themselves.
- Some parents of demigods are able to see through the Mist, while others (like Tristan McLean) are unable to.
- As revealed in The Crown of Ptolemy, the Mist is actually the uppermost layer of the Duat. This connection is first hinted at in The Staff of Serapis.
- It is noted that Carter Kane saw flying horses near the Empire State Building or Olympus. It is unknown if the effects of Mist don't apply to him because he is a magician or if it was really his imagination. However, Carter was able to see Riptide in The Son of Sobek, implying that magicians can see through the Mist a little bit.
- In The Ship of the Dead, Alex Fierro refers to the Mist as the "Glamour".
- Hearthstone stated in The Sword of Summer is that the Mist is between fire and ice which translated to Ginnungagap but he couldn't explain more in sign language.