Kai Nijuuri is a slim and handsome man, but he is narcissistic and egotistical through and through. He loves himself so much that he even carries around a bolster with of picture of himself stamped on it and snuggles with it whenever he is down. Of the three, he is maybe the only and most perverted one of the three who always erect his nipples to hilarious lengths. It functions neither for offensive (maybe for some people) or defensive but just for comedy relief as his nipples tend to erect when ever he is excited.
Ever since joining Holmes Detective Academy under the disguise as Kai Nijuuri, a teacher of the school. Though not exactly flirting, Twenty's excessive demands for all of the students attention with stripping constantly to have their eyes on him often results in them zoning him sometimes not even listening to his lessons. During the night however he is the dandy Gentlemen Thief, the left slight of hand of Lady Arsene.
Twenty's Toy is the ability to allows him to disguise himself perfectly to infiltrate any facilities for a heist. But the true testament of his stay in the The Gentlemen Thief Empire is his skills as a magician being an expert in handling a great number of tools, cards and flying machines at his disposal.
- Twenty strips very often in during heists in front of the Milky Holmes. Along with the erecting nipples, it is a mystery why the girls have not yet pointed out Kai Nijuuri is Twenty.
- Undercover as a teacher, his name is based after Edogawa Rampo's Fiend of Twenty Faces.