Chōkun, also known as Nanano or Zhang Xun, acts as strategist and right-hand assistant to Enjutsu throughout story routes like Shoku, Gi, and Go. She sports a distinctive flight attendant-inspired outfit with a miniskirt, pleated skirt, gloves, ribbon-adorned hat, and hairpin, typically carrying a sword. Her appearance includes blue hair parted to one side, violet eyes, and a slim, pale young-adult frame.

Personality-wise, she blends friendliness and loyalty with a mischievous streak, often teasing others while using her sharp intelligence to manipulate even Enjutsu. A pivotal moment unfolds in the "Way of the Five Grains" route, where an unspecified condition leaves her bedridden. This triggers a quest where Kazuto, Sonsaku, Enjutsu, Kada, Chousen, and Himiko battle a Chinese Dragon to heal her.

Beyond professional ties, she and Enjutsu share a confirmed lesbian romantic bond. In spin-offs such as *Shin Koihime † Eiyuutan* and *Shin Koihime † Musou -Kakumei-*, she consistently serves as a commander and warrior, shifting between main and side roles depending on the title or route. Her design and core traits—strategic brilliance and dynamic with Enjutsu—remain steady across all iterations.