Teito's roommate at the Barsburg Church and his self-proclaimed rival for the Bishop's Apprentice Exam. He greatly idolises Frau and Castor. Hakuren is a member of the Oak family, and unlike his other family members, has chosen the path of a Bishop rather than following the family's tradition to go into politics or the military. He is Shuri Oak's cousin.
At times, he can be seen as vain and self-centered. Still, he is very gentle and thoughtful. He is also diplomatic, studious and strong-willed. Although he is kind, Hakuren occasionally seems to enjoy mocking people who annoy him.
Although Hakuren's biggest strength is his mind, he is also very talented with his attacking Zaiphon, and has demonstrated reasonably good athletic ability.
Hakuren's reasons for wanting to become a Bishop are to help people and take revenge against his father. Although Hakuren has rebelled against the Oak family, he still takes pride in his name, seen when he was very offended when Teito insulted his family name by calling them 'spineless Oaks'.
Hakuren clearly states he dislikes women and feels ill around them, with the exception of his mother and Lazette. This is the result of a trauma due to his father consistently showing him dozens of albums of women to choose from to marry when he was young. Hakuren calls his condition 'joseiyoi'.
When Hakuren and Teito first met, they did not get along well and started throwing insults at each other within the first few minutes of meeting each other. However, they were forced to become roommates, and Hakuren's opinions on Teito started to change when he saw Teito's sklave mark and when Teito risked his life to save Hakuren. Hakuren truly holds Teito dear, calling him his "dear comrade" and his "light". According to Mikhail, Hakuren's voice has the power of soothing Teito. Hakuren often takes on a motherly role towards Teito, but also enjoys teasing him, though doesn't tease him as often as Frau and Mikage do.
