Like any butler, Rentarou is devoted to his lady and this shows in his interactions with her. He is still to stoop low in order to ensure that his mistress's goals are met.
He wears a black suit with long coattails, and black slacks, with a white dress shirt and a red bowtie. His hair is light gray and slicked back, and wears a monocle over his right eye.
While in disguise, he employs a red sleevless jacket, sunglasses, and a curly hair wig to fool those around him.