Death Busters

The faction operates as a hidden cult rooted at Mugen Academy, the school and laboratory Dr. Souichi Tomoe built over the Omega Area of Mugenzu, ground they revere for its resemblance to the Tau Nebula. Their structure climbs from Pharaoh 90 at the summit down through the commanders Kaolinite and Mistress 9, the five elite sorceresses of the Witches 5, and the disposable Daimon foot soldiers. Tomoe himself serves the group while secretly playing host to the Daimon Germatoid, and his daughter Hotaru becomes the vessel for Mistress 9.

Everything the Death Busters do points toward one aim: call up Pharaoh 90 and convert the planet into a second Tau world. To that end they treat human beings as raw material, implanting them with Daimon Eggs and harvesting souls or Pure Hearts. Their own life force flows from the Taioron Crystal, yet they covet the far stronger Silver Crystal precisely because its power can rouse their sleeping master. A cold, ranked hierarchy governs them, and any member who climbs high enough can ascend to the rank of Magus.

In the manga, the Death Busters reach Earth on the very day Tomoe experiments on Hotaru to rebuild her as a cyborg. A lightning strike transforms his assistant Kaori Kuromine into Magus Kaolinite, and the group joins Tomoe in gathering souls to summon Pharaoh 90. They plant Daimon Eggs that erupt from their hosts, brainwash the students of Mugen Academy, and produce five perfect Daimon known as the Witches 5. A Magus can commune with Pharaoh 90 through the Water Mirror at the academy's peak, which warns Kaolinite that uniting the three Talismans brings ruin. Once Hotaru fully becomes Mistress 9, she swallows Chibiusa's Silver Crystal and channels part of its power to wake Pharaoh 90, who bursts from the mirror, levels the academy, and embeds itself in the planet. Sailor Moon dives into the entity wielding the Silver Crystal and the Holy Grail, awakening Sailor Saturn from within Mistress 9's monstrous shell. Saturn wrenches Pharaoh 90 free, destroys it, and seals the portal to the Tau Nebula forever, ending the organization.

The anime keeps Tomoe at the helm, pushing his followers to secure the Holy Grail said to form when the three Talismans converge, treasures locked inside Pure Hearts and coveted by Sailor Neptune and Sailor Uranus. Hotaru, the reborn Messiah of Silence, stirs when the Grail appears and later consumes Chibiusa's Pure Heart Crystal. By then the Witches 5 have all been eliminated, and Uranus and Neptune drive Germatoid out of Tomoe while sparing him. Mistress 9 succeeds in drawing Pharaoh 90 to Earth, but Hotaru struggles free, rouses the spirit of Sailor Saturn, and destroys their shared body. With Sailor Moon's aid she enters Pharaoh 90 and expels it from the world.