Rubbeus was originally in charge of the mission to capture the "Rabbit" Chibi Usa. The Ayakashi sisters were all under Rubbeus, and they reported to him and carried out his orders.
Rubbeus was downright evil and manipulative. He sent the four sisters to do the work but planned on getting all the credit for himself if they were successful. He deployed them to potentially dangerous situations with the thought that they were expendable. Rubbeus would then claim the fruits of their labor if they died.
Rubbeus knew that Catsy was in love him. He used Catsy's feelings for him to control her, but he broke her heart in the end by telling her he did not do "stupid things like loving somebody...".
Rubbeus was able to capture the sailor soldiers and use them as bait for Sailor Moon. Sailor Moon and her group managed to escape Rubbeus' exploding UFO, but Rubbeus was left there by Emerald to die because of his failure.
