Daimons, also referred to as Daimon Heart Snatchers or just Heart Snatchers, are the monsters of the week sent by the Bureau of Bad Behavior to extract Pure Hearts. They are created from Daimon pods, and combined with an object to form a monster. When the monster is destroyed, the pod sprouts up and then cracks, neutralizing it of all energy. All are destroyed by Sailor Moon's Moon Spiral Heart Attack or Rainbow Moon Heart Ache, except Mikusi and Darumah. The former is destroyed by Sailor Neptune and Sailor Uranus, and the latter is destroyed by Sailor Jupiter.
Kaorinite takes a Daimon pod given to her by Doctor Tomoe, and implants it in an object to turn it into a Daimon. That Daimon uses a star symbol on them to extract the victim's Pure Heart. When the Daimon is destroyed, the item returns to normal, the pod sprouts up and then cracks, neutralizing it of all energy.
Eugeal's Daimons are created by Doctor Tomoe when a Daimon pod and item are placed inside the Heart Snatcher oven. Eugeal then takes them in a box while driving a car around. She extracts the Pure Hearts with a gun, sending the Daimon to fight the Sailor Scouts should they interfere. Like before, with Daimon destroyed, the pod sprouts up and then cracks, neutralizing it of all energy.
Mimet's Daimons are created in the same way as Eugeal's are, except they, like Kaorinite's Daimons, suck out Pure Hearts. These Daimons suck the Pure Hearts out through the victim's mouth, and are kept in an attache case carried around by Mimet. As in all cases, with a Daimon is destroyed, the pod sprouts up and then cracks, neutralizing it of all energy.
The most powerful Daimon is Germatoid, who was possessing Doctor Tomoe the whole time (and is the only male Daimon). He is not considered a monster of the week, as he technically appears in every episode before his death, possessing Doctor Tomoe.
One Daimon survived the fight with Pharaoh 90, and merged with the Daimon oven to become Rangy.