Age: 16
Height: 149 cm (4' 10")
Weight: 33 kg
Blood type: A
Birthday: January 8
Ruka Suirenji is a dance idol and a doujinshi creator. She is friends with Chiharu. Ruka excels at drawing, having created the doujinshi that Nagi and Chiharu were selling at a convention under the pen name Fly Dolphin. Additionally, she is a renowned idol, capable of singing and dancing simultaneously, with a large fan base. Her personality is characterized by determination and diligence, exemplified when she insisted on returning to work despite her injuries and when she resolved to handle her own misfortune.
Chiharu revealed that Ruka shares a similar past with Hayate, having been abandoned with a substantial debt of 150,281,000 yen. She dreams of becoming a professional manga artist. The pen name Fly Dolphin was originally the name of the performance office owned by her parents.
In chapter 382 of the manga, Ruka realizes she is in love with Hayate and kisses him. In chapter 383, she confesses her feelings to him. However, she is rejected because Hayate works as a butler for Nagi. Consequently, Ruka challenges Nagi to see who can sell more copies of their doujinshi, with the prize being an amount equivalent to Hayate's debt.
Nagi won the doujinshi contest. Ruka still had one copy left out of her 100, suggesting she might have done this intentionally since she saw no signs of Hayate quitting his job as Nagi's butler. This is hinted at in certain panels of the manga, which show she earned 20,000 yen from selling doujinshi at 200 yen each, indicating she could have sold all of them.
