Fuka Ayase is a character from the Yotsuba&! manga. She is 16 years old and the middle child of the Ayase family; however, despite this, she is the most responsible, even more so than her older sister, Asagi. She is shown to be a friendly, considerate, and quite unfortunate individual. She has appeared in every volume of the series thus far.
Fuka first appeared in a one-shot manga published in 1998 and two webcomics called "Try! Try! Try!", where she appears substantially similar as at the start of Yotsuba&!.
Fuuka is the second oldest and the most responsible of Ayase sisters, and during Yotsuba's first visit to her school, one student refers her as the vice-president. She participates in many school events and has also sacrificed several experiences as a result of her schooling, which explains her absence in the hot air balloon.
She finds herself frequently helping the Koiwai's, even though she does not intend to and is more flustered by their eccentricities than anyone else.
Fuuka is often teased by the other characters, especially about her fashion sense and sense of humor. She is fond of making bad puns, which irritates Asagi, and wearing shirts with odd or interesting graphics.
- Yotsuba Koiwai (friend/neighbor)
Fuka is a usual playmate for Yotsuba and one of the first to meet her in the Ayase family, besides her little sister, Ena. She also serves as somewhat of a parental unit to Yotsuba, constantly taking care of her, particularly when Mr. Koiwai is too busy to handle her himself. Despite Yotsuba's often outrageous behavior and actions, Fuka is shown to like her very much and knows that she has the best intentions.
- Asagi Ayase (sister)
Asagi is Fuka's older sister. She seems to dislike Fuka's sense of humor and fashion sense, and because of this, ridicules her often.
- Ena Ayase (sister)
Ena is Fuka's younger sister.
- Mr. Koiwai (neighbor)
It is hinted several times that Fuka has a slight crush on Mr. Koiwai. For example, when Fuka decides to speak into Yotsuba's communication cups, Mr. Koiwai happens to be directly on the other line. The two converse for awhile, before Asagi walks in on Fuka, who nervously shouts: "It's not like that!"