In the manga, the Death Busters used living hosts for Daimon eggs. Eventually the hosts would be unable to hold their original form and the Daimon would take over their body, transforming them into terrifying creatures. Once the Daimon was killed, most of the time the host would revert to their original form, still alive. However, the Witches 5 themselves were considered perfect Daimons, having completely and willing merged with the Daimon implanted in them. After Eudial and Tellu were severly damaged by the Senshi, they took on unique monstrous Daimon forms and would be destroyed by the Senshi. Kaolinite and Professor Tomoe became terrifying Daimons when they were forced to confront the Sailor Senshi directly. Daimons could be planted into a host and remain until the Death Busters activated them in order to assist in fighting the Senshi.
In the anime, their objective was to extract Pure Heart Crystals from people. They were sometimes referred to as just Heart Snatchers. They started out as pods created by Professor Tomoe Tomoe and when infused with an item, it would become a Daimon. When the victim in question made contact with the possessed item, the Heart Snatcher emerged. Kaorinite's particular Heart Snatchers would immbolize their victims and extract the Pure Heart Crystal using a beam of energy fired from a black star tattooed somewhere on their bodies. Once destroyed, the transformed object was restored. With two exceptions, all of them are destroyed by Sailor Moon using Moon Spiral Heart Attack (and later, following the defeat of Eudial, Rainbow Moon Heart Ache). Rangy was destroyed by Moon Spiral Heart Attack like those working for Kaolinite and Eudial. Mikuji was destroyed by Sailor Uranus and Sailor Neptune, and Daruma was silenced by Sailor Jupiter's Sparkling Wide Pressure attack.
After Kaorinite was killed by Sailor Uranus, Eudial, the first of the Witches 5 took over. From this point forward, Daimons were created by Professor Tomoe with a Daimon pod and an object put in a machine called the Heart Snatcher Oven. Unlike Kaorinite's Daimons, Eudial's Daimons were merely summoned to fight the Sailor Senshi whenever they tried to fight her, who did the Heart Snatching herself with a gun. Soon Eudial was killed by Mimete, the second of the Witches 5, who also took over. Like Kaorinite's Daimons, Mimete's Daimons did the heart snatching for her, except instead of using star symbols as Kaorinite's Daimons did, Mimete's Daimons sucked the Pure Hearts out through the victims' mouth and ate them.
After the death of Mimete, the use of Daimons fell out of use to the remaining members of the Witches 5, Tellu, Viluy and Cyprine, who simply just used their own creations (with the exception of Cyprine, who teamed up with Ptilol to fight the Sailor Senshi). No more Daimons appeared until Mistress 9 awakened, using all remaining Daimon pods (except one) to create Daimons in the form of gelatinous monsters which formed a barrier around Infinity Academy and attacked the Sailor Senshi. It was they that blew up the helicopter, killing Sailor Pluto. They were destroyed by the Silence brought on by Pharaoh 90. After his death, only one Daimon pod remained, combining with the Heart Snatcher oven to turn into a Daimon named Rangy, who extracted Pure Heart Crystals from people until Sailor Moon destroyed her, causing the Heart Snatcher oven to explode.
- The Daimons appear in the video game Sailor Moon: Another Story. Mikuji, Steering, Octave, Dovlin, Taiyan, Cenicienta, Chagama, Daruma, Doorknobder, U-Henshū, U-Baulla, U-Ndokai, U-Ikasaman, and Uchoten appear as common enemies. One Cenicienta that was referred to as "Persian Cut" was the first boss of the game where it attacked OSA-P.
A Daimon called "Gondola" appeared in "Pretty Soldier Sailor Moon S ~ Usagi - The Path to Become the Warrior of Love."
Like the original anime, Daimons originate in a Daimon egg that needs to be planted into a host in order to emerge. However, the eggs are planted into a living being, where the host is enveloped into the Daimon when it hatches and takes form. A Daimon egg could be planted in a host, but not hatch until called upon by a member of the Death Busters to fight for them. Daimons take on mostly similar generic forms, however there was one instance where a cat was possessed by a Daimon and took on feline features that differed from other Daimons. Usually after the Daimon is destroyed, it vanishes, leaving the host unharmed and the egg is ejected and disintegrates. However, Daimons, like the Witches 5, have perfectly merged with their host so once destroyed, there is no trace left behind.
- In the original anime, the Daimons appeared as monstrous humanoid women, while in the manga and in Crystal, they had grotesque giant worm-like appearances.
- A Daimon that appeared in a flashback in episode 106 closely resembles all the generic Daimon in the manga.