|Name (Kanji)||桐山 杏|
|Family||Yui - Older Sister|
|Seiyū|| Sakura, Ayane (佐倉 綾音)
Tiffany Terrell (English)
|Novel Debut||Volume 3, Chapter 2|
|Anime Debut||Episode 1|
Kiriyama Anzu (桐山 杏) is Yui's younger sister. She is a 2nd year middle schooler.
Anzu has a similar appearance to her older sister and the two have matching green eyes, though her light-brown hair is trimmed to chin-length. Despite being two years younger, Anzu is noticeably taller than her sister.
- Kiriyama Yui: Anzu is shown to be a caring sister towards Yui, often checking up on her, though it is implied she is unaware of her sister's androphobia. Anzu admires Yui for her karate skills and was disappointed when her sister quit martial arts. When Yui eventually returns to karate, Anzu helps her train.
- Mihashi Chinatsu: The two work together to get Yui back into karate in Kako Random. In Precious Time, Anzu and Mihashi team up as a special pair for the Couples Battle Royale.