Same appearance as the manga.
He first appears in Rei's mystic fire while she was meditating. He physically appears in the fifteenth episode to find Chibusa and succeeds in abducting Sailor Mars and taking her to his master on planet Nemesis.
He intends to reveal Wiseman for who and he really is one day.
He soon realizes that there is more to Wiseman than what he sees.
Rubeus went against Wiseman, than attempted to escape so Wiseman then destroyed him.