Hiyori Sarugaki is a former lieutenant of the 12th Division under captains Kirio Hikifune and Kisuke Urahara. She viewed Hikifune as a mother figure, and thus initially refused to accept Urahara as her replacement. Hiyori is a tiny, blonde-haired girl with a fierce temper and violent tendencies. Her hair is worn in pigtails and she wears a red jogging outfit decorated with the first kanji of her name (猿 saru, meaning "monkey"). She also has a tiny fang on the left side of her mouth. Hiyori often abuses Shinji Hirako, usually by slapping him with one of her sandals or using him as a human shield when necessary. This behavior dates back to her time as a lieutenant, despite the fact that Shinji outranked her then.

Hiyori took the longest to defeat her inner hollow out of all the current Visoreds (excluding Ichigo, who took about the same amount of time), at 69 minutes and 2 seconds. Hiyori's zanpakutō is standard in appearance with her tsuba decorated in small hearts, a contrast to her not-so-girlish personality. She normally wears her sword from her right shoulder, like Ichigo. Her hollow mask looks like that of a normal hollow mask with a large horn and pink like stripes on the top.