Rubeus First appears in english episode 54:Serena Times Two.
With him are the 4 blackmoon sisters.They have been sent to tokyo in the past by Wiseman.
Rubeus and the sisters have been sent to the past to alter the future for the Negamoon, a dark counterpart to our Moon. To accomplish this, he must do one of two things.
One: he must capture Rini, a princess who is key to the fate of the future, or two: take over key points in the past and prevent the future from happening right.
His missions are to get Rini and the Silver Crystal.The sisters don't know it, but Rubeus is just using them. He doesn't care about them, just the mission. He'd sooner blast them with his energy bombs than go shopping with them.
Eventually, Rubeus' continuous failures get the attention of his superiors, and Emerald relays to him an ultimatum: Finish the job in 24 hours…or else. Aided by the Wise Man, an opportunity arises, and Rubeus manages to take advantage of it, capturing Rini and four of the Sailor Scouts. However, Rubeus underestimates Sailor Moon and the combined abilities of the Sailor Scouts. In desparation, Rubeus sets his ship's self-destruct mechanism, but the Sailor Scouts are able to combine their powers and teleport Rini and themselves to safety, trapping Rubeus in the ship as it explodes. Rubeus dies in english episode 67: Rubeus Strikes Out.