Yuki Watanabe works as a teacher and homeroom instructor at Akemi's school. She develops romantic feelings for Akemi and seizes an opportunity during a house visit, initiating intimacy while Akemi's mother is away shopping. Watanabe exhibits impatience and assertiveness in pursuing her desires, acting decisively without hesitation. She maintains a secondary identity under the alias Jun Nakatani, revealing she is intersex and transitioned from male to female. She states she was previously mocked for feminine traits but now leverages her appearance to move undetected among women.

This dual identity aids her actions during Akemi's wedding, where she suggests their relationship could continue without suspicion. Within the anthology, she appears in "Alimony Hunter" involved in a complex three-way dynamic with ambiguous identities. She resurfaces as a teacher in "Cherry Lips" under her alias Jun Nakatani. Her storyline concludes in "Virgin Road," where she engages in a last-minute encounter with a bride in a chapel back room; the bridegroom is also acquainted with Jun Nakatani.