Ui Hakosaka is a member of the in-story idol group Gentlemen within the series narrative. His full name is written as 葉小坂初 in Japanese. The surname Hakosaka (葉小坂) incorporates the kanji for "ha" (葉 – leaf, plane, lobe, needle, blade, spear, counter for flat things, fragment, piece), "ko" (小 – small), and "saka" (坂 – slope, hill). His given name Ui (初) translates to "first time" or "new". As part of Gentlemen, he engages in performances and activities related to the group's role in the entertainment industry setting. The group performs the opening theme song "Dreamy Life" for the television series.