Mirai is a short and petite girl with light brown eyes and pink hair, which is styled in a bob-cut with a full fringe. At school, she dons a loose pink cardigan over the school uniform and black tights or similar hosiery. However, Mirai began to attire a vest-like sweater over her school uniform, identical to the color of her cardigan.
Mirai wore the cardigan to conceal a bandaged wound (a gash on the right forearm in the light novels; a round wound on the right palm in the anime) which she always prepares whenever she needs to use her ability. In the light novels, she also wears a set of bracelets to secure the bandages to her wounds. She then began using her ring to activate her ability.
Her most distinguishable accessory is the pair of red thick-rimmed glasses that she proceeds to adorn at all times, which she soon changes to gray for a while before she soon changes to red again.
Clumsy and a bit aloof, Mirai rarely stands out in school. In fact, she struggles pretty much in life; she has to earn her own money to make ends meet, but her constant fear of actually encountering a Youmu used to prevent her from earning an income from slaying Youmu, which most Spirit World Warriors take on as part of their profession. To make things worse, her hobby of writing blog articles about bonsai is often ridiculed in the Internet. In contrast, Mirai is a focused Spirit World Warrior, although her clumsiness still shows. Her movements in battle demonstrate a certain degree of knowledge in how to fight, although she lacks the experience in actual combat due to her issues with Youmu encounters. After bonding with those around her, Mirai began to feel more confident about defeating Youmu and became quite the experienced Spirit World Warrior. She is fond of saying the words Fuyukai desu which stands for this is unpleasant or how unpleasant.
Mirai is the sole survivor of a cursed clan with the ability to control blood. She was adopted by the Inami family. But when the Hollow Shadow possessed her best friend, Yui Inami, Mirai killed her in an attempt to save herself. After that, Mirai was hated by the Inami family, especially by Yui's little sister, Sakura Inami. Nonetheless, after one of their battles, Mirai had convinced Sakura to stop getting revenge on Mirai.
- Mirai was born with the ability to manipulate her blood in various ways such as shaping and solidifying it to form constructs (She is limited to this ability as to how much blood she has). She can also use it to burn through things, as shown in a few episodes.
Mirai first met Akihito on the roof of the school building while trying to suicide. Afterwards she tried to kill him only to find out that he was basically immortal. She went on trying to stab him for practice until eventually they became friends. Akihito was the one who got Mirai over her fear of Youmu and even though she's always complaining about how unpleasant he is, she still cares about him.
After finding out what Mirai has done to her older sister, she began to hunt her down, planning to kill her and get revenge for Yui. After a battle with Mirai, Sakura came to realize that she is not a Spirit World Warrior and becomes friends with Mirai, eventually developing a bond with her. She currently lives in Mirai's apartment. She seems to care about Mirai to the point of frantically asking where she was and kicking Akihito hard when he didn't answer.
Mirai meets Mitsuki after Akihito introduces them to each other. Although Mitsuki was cautious of Mirai at first, she still develops a bond with her after getting to know her better and often has girl talks with her from time to time.
- She often says the phrase, "Fuyukai Desu! (不愉快です!)" in English : "How unpleasant!"