Ryuu is a young bartender/bar-owner who has an incredible way of telling what a person is thinking and feeling, and what they want (and often need) to drink. That ability mixed with his kind, honest personality makes him the ultimate bartender.

Ryuu is a genius bartender who helps the people who come into his bar. Although not thoroughly explained at first, Ryuu actually runs the bar by himself, and Eden Hall was his first bar. He worked as an assistant for a senior bartender before he opened Eden Hall, and that gave him the experience he needed to handle the job. In episode 9, it is revealed that Ryuu has in fact made a mistake by serving an incorrect cocktail to a man, as he requested a different drink afterwards, despite his almost flawless outlook. Due to this, for every year after he opened Eden Hall, Ryuu has reserved that one special night for that man,who was Eden Hall's first customer. Often, Ryuu maintains his composure and throughout the story, puts on a brave and sincere effort to help the customers who fret and seem disturbed in his bar. He has been shown to handle all sorts of spirits and know most of the history of the drinks he serves. Ryuu is also known to serve the "Glass of the Gods," and being entitled to this, made Eden Hall a pleasurable venue for customers seeking the menu of their hearts. According to the manga, Ryuu is 26 years old.