|Appearance||The Devil's Game|
|Fate||Erases self from existence and sucked into game|
Mio appears to be a tomboy, having a short, spiked hairstyle that frames her face with a cowlick and messy bangs. Her eyes are rounded with very short lashes.
She wore multiple outfits during the story, all with similar elements. Her original outfit consists of a plain white top with camoflouge shorts, black leggings, and a jacket or hoodie.
Mio is a friendly girl who initially comes off as depressed and lonely due to feeling excluded. She worried that her friends would think she was boring and desparately wanted a game more than anything. She is brash with her gestures, but easily anxious -especially around her crush- and deep down she is has a sensitive side.
Mio attends class 6-B, where everyone but her has a game console because her mother is convinced she won't improve her bad grades. She worries that everyone will forget about her soon but one day, on the way home she comes across a black console on the ground and picks it up. She eventually realizes that every decision that she makes in game also occur in real life after she finds money in game and when she finds some in town, with both situations rewarding her after she returns it. She decides to use it to her advantage to improve her grades and get attention from Abel.
But after a little boy is killed instead of her, she begins to learn how dangerous the game is. By now her friends have given up on her for abandoning them, and her health is deteriorating. She is warned by her teacher to head home in groups with other classmates due to a dangerous man having been seen in town- but after a fight with Yukari, she finds herself confronted by him. She takes shelter in a girls restroom as she watches a similar event happen in game until she is asked a choice: Reset the game or die. Seeing no other options she chooses to reset the game thinking that everything will be fixed, but just as the stall door opens it is revealed to have been her classmates in disguise. But as Yukari comes to tell the classmates off and help Mio, she realizes she has vanished; the only thing left in her place is the game console.
- She makes a cameo appearance at the end of Black Forum, chatting online with Anna from The Kind Mama's House, and Yomi, discussing the victim of the story, Misa.
- She is the very first protagonist in Zekkyou Gakkyuu. She is also the first of many:
- She is also the first protagonist to become a victim.
- The first protagonist to have been punished for their own selfishness/greed.
- The first protagonist to find a dangerous item.
- The first protagonist to have friends but somehow does something to lose them or have lost them prior to the story.