Aki (亜季 Aki) is Haruna's younger sister and a tsundere (a character who flips between a "cold" side and a "warm" side). She initially didn't believe that Hakone was a hot spring spirit. Trivia Edit Aki sounds like the Japanese word for "autumn" (秋 aki). Aki's name also contains the character for "season" (the time period). References Edit ↑ http://www.hakone-chan.jp/character.html (Japanese) ↑ Hakone-chan ep 2 Retrieved from "https://onsen-yousei-hakone-chan.fandom.com/wiki/Aki?oldid=142" Categories: Characters Add category Cancel Save Community content is available under CC-BY-SA unless otherwise noted.