(佐々木 禎子, Sadako Mio, lit. "no meaning"): is a Shinobi hailing from Amegakure. Originating from a small family of pub owners, Mio was surrounded by alcohol her entire life. Strangely, rather than the negative effect you'd presume it would give her, Mio loves alcohol. She is usually seen in the bars around Amegakure drinking to her hearts content, and on more occasions than one, has arrived at missions completely pissed. Mio is extremely loud and can sometimes come across as violent, though that's mostly down to the alcohol.. When she isn't drunk, she's hungover, and extremely grouchy and anti-social. When she isn't either of those, Mio is.. well, Mio. A capable fighter, a surprisingly good tactician, and a fun person to be around. That said, she can be extremely serious if the situation at hand requires her to be, and won't take shit from anyone.
(カード本術, Kādojutsu):(lit.'Card Techniques') are techniques that have been passed down in Mio's family for many years. They are an old set of techniques based around Fūinjutsu and Kuchiyose, except rather through the generic ways, use cards. Users generally carry around standard card decks, though the cards aren't your typical playing cards. With these cards, users of Kādojutsu are able use the cards as shuriken, summong weapons, absorb techniques for later use (limited), and various other things. Unlike regular cards, they are extremely hard, comparable to steel and razor sharp. They cannot be burnt and aren't effected by water, though can be destroyed by a direct hit from electicity. The traits of the cards, such as size and weight can be edited by the user until they see fit. It should be noted that users of Kādojutsu are unable to utilize chakra natures. As Mio's primary fighting ability, she is naturally good with them.(医療忍術, Iryō-Nin): (lit.'Medical Shinobi') are ninja who specialize in medical treatment and use of medical-oriented jutsu to heal others. Becoming a medic-nin requires high intelligence and excellent chakra control. A medic-nin is trained to avoid getting injured in any way, for the reason that if they are injured, then there would be nobody to heal the other members of their team. Medic-nin accompany other ninja on high ranking missions to increase the survival rate of the squad. The knowledge of a medic-nin can be used for a variety of purposes. The Inuzuka's veterinarians specialize in the treatment of ninken. Medicinal knowledge can be used to create deadly poisons. Field medical-nin, when in the field or on the battlefield, are equipped with Medical Pouches in order to carry medical supplies as well as their weapons. (体術, Reibi): (lit.'Zero-Tails') is the name of the Noh masked leech-like spirit dwelling inside Mio. Unknown to her, it feeds off of her negative emotions, that she suppresses trough the consumption of alcohol, and the source of alcohol problem. The Zero-Tails is an evil spirit created by the dark thoughts and feelings of the downtrodden people. This parasitic creature will seek out and feed upon any negative emotions within one's heart and allows the spirit to create Dark Chakra (闇のチャクラ, Yami no Chakura). When anyone near the Zero-Tails is emotionally unstable, it will inhabit their body and take them over. Mio has no idea that this monster lives inside of her.