Professor Souichi Tomoe is the leader of the Death Busters, the founder and owner of Infinity Academy, a famous scientist, the father of Hotaru Tomoe and the husband of Keiko Tomoe. He becomes a Daimon in his last chapter, called Germatoid. This is the original depiction of the character created by Naoko Takeuchi.
Souichi Tomoe has white hair and wears a white shirt with a tie, khakis and business shoes. He wears a lab coat and wears glasses with the right lens displaying an eye, possibly to conceal an injury.
As Germatoid, all his human features are gone, replaced by a monstrous figure, with spikes poking out from his body. He has sharp claws, and the Death Busters symbol displayed on his forehead.
In the manga, Tomoe was a scientist until, as Kenji Tsukino recalled, he was thrown out of the scientific community for dodgy experiments. After selling some of these findings, he purchased the area where he built his labs and Mugen Gakuen. He continued with his research but a lightning strike caused a fire there, which killed his wife Keiko and left his daughter Hotaru badly injured.
Tomoe saved his daughter using what appeared to be a mix of cybernetic and genetic technology. He also implanted a Daimon Egg in her at this time, the eggs having arrived with Pharaoh 90 during the lightning strike. They infected his assistant, Kaorinite, as well as himself.
After this he focused on the creation of his "Super Beings,"using a variety of scientific techniques including genetic, pharmacological, and cybernetic processes. Human bodies were used as vessels, but he also made several Daimons from the Eggs alone: the Witches 5. He experimented on himself as well, creating a fusion of human and alien.
When Super Sailor Moon arrived at his lab with the Outer Senshi, Daimons attacked and Tomoe changed into a creature called Germatoid. Sailor Moon killed him with Rainbow Moon Heartache, and Hotaru was briefly seen saying goodbye to her father, whom she realized had disappeared a long time ago, after her mother's death.