Konan

is the only female ninja in Akatsuki and the only member to call her partner, Pein, by his name. "Ko" can mean child or sin. "Nan" means difficulty or hardships (appropriate due to the traumatic childhood she had).

Background
When she was younger, Konan, Nagato, and Yahiko were left orphaned by one of Amegakure's many wars, forcing them to fend for themselves. The three eventually encountered the Sannin, who gave them some food. Konan impressed them by making an elaborate flower out of the paper wrappers left behind. After Nagato killed the Rock Chunin, Jiraiya took them up on their offer and began to teach them Ninjutsu. Jiraiya believed Konan to have died with Nagato and Yahiko some time later, and upon seeing her again years later, he comments on how beautiful she has become, as well as her improvement in her paper jutsu.

Personality
Konan has a relatively mysterious personality. Mostly, she is stoic, calm, and level-headed (much like Pein). As a child, she was bright and relatively cheerful compared to the tough Yahiko and sensitive Nagato. However, the trauma of events since then have left her more serious and solemn and she never spoke until her most recent appearances.

She does seem to be more empathic than other Akatsuki members, as she appears sad whenever she has been reminded of her past. She also expresses a great deal of loyalty and courtesy to Pein (which he always returns), doing his bidding without question and looking out for his well-being. She seems to act as an intermediary between Pein and Amegakure, the villages having given her the title "God's Angel" for this reason. Fans suspect that she and Pein harbor feelings towards one another as both converse the way a married couple would. Moreover, Pein freed her from Jiraiya's grasp without hesitation or request; and Konan is never seen talking to any Akatsuki member other than her partner.

She also has the ability to read Pein's emotions without him facially expressing them. As soon as Madara ordered Pein to capture Naruto Uzumaki and the Nine-Tailed Demon Fox, she could tell right away that there was something about the order that upset Pein.

Infiltration of Amegakure
Konan appears when she tells Pein that Madara Uchiha has arrived. When it starts raining after Madara leaves, she comments on how the rain makes it seem that the village is crying. She later appears when Jiraiya infiltrates Amegakure, entering the rain shower and becoming detected by Pein. When Pein stops the rain, Konan uses her abilities to find Jiraiya while Pein is changing bodies. She returns to inform Pein that it's Jiraiya, and goes to hold him off for Pein. She attacks Jiraiya with paper spears, but he sees it coming and uses his Toad Fire Technique to stop the spears. Jiraiya remembers her, complimenting her on her power and beauty, commenting that she had become "one hell of a woman." Jiraiya easily stiffens her body with oil, but she is saved when Pein appears to wash the oil out. She regroups with him after he defeats Jiraya.

Hunt For The Nine Tails
Later, in Pein and Konan's home, Madara pays them a visit to see what was keeping them. After explaining Jiraya's invasion, Madara quickly mocks Pein; Konan then quickly defends Pein once again reminding Madara that Pein is "invincible". After Madara leaves, Pein tells her to get ready to go to Konoha.

Abilities
Konan is a shinobi of some power, as she is held in high regard by her partner Pein. However, Jiraiya held her off with relative ease. She has a natural talent for origami, as seen with the paper flower she keeps in her hair. As a child, after training with Jiraiya, she was able to form paper weapons infused with her chakra, which could pierce flesh easily.

As an adult and member of Akatsuki, her powers have grown considerably. Her entire body now can transform into thousands of sheets of paper, which she can control at will and form into any shape (Her clothes transform too, thus suggesting a unique style of transformation jutsu is used). To travel long distances, she can mold them into butterflies or planes for powered flight, and to attack, the sheets can form arrows, shuriken, or kunai. She can also restrain opponents by blanketing them in sheets restricting their movement. Befitting (and likely inspiring) her title as 'God's Angel', the papers can also form large wings for flight or further weaponry. As a whole, she is probably quite difficult to harm since most physical attacks would go straight through her, but this has yet to be confirmed.

She does have weaknesses, though, primarily water, since paper clings to itself and looses stiffness when wet. To negate this, Pein has to stop the rain for her whenever she moves around the village. Jiraiya easily negated her abilities by smothering her in oil. Furthermore, she appears vulnerable to Fire Release techniques.

Trivia

 * Even though she is an Akatsuki member, Konan (like Pein) ironically is not a missing nin since she belongs to Pein's Amegakure; a world recognized village.
 * Apparently, Madara and Konan are not on good terms with each other as he always questions Pein's abilities and she immediately scolds him for it despite Madara being her and Pein's benefactor.