|The Female Titan. It's an all-purpose unit, capable in every area. In addition to high mobility and endurance...the Titan's hardening abilities combined with Leonhart's martial ability makes for an incredible destructive force. She's also able to summon Pure Titans, though her range is limited.|
|— A Marleyan analysis of Annie's Female Titan|
Similar to the Founding Titan and Zeke Yeager's Beast Titan, the Female Titan is able to exercise some influence over Pure Titans through a scream-based ability; it possesses the ability to attract Pure Titans. Annie Leonhart used this ability to gather Titans on Paradis Island to the Walls during the fall of Wall Maria.
The downside of the attraction ability is that once the Titans following the Female arrive at her location, they will attack the Female Titan and eat its body. Under normal circumstances, this could lead to disaster for the user of the Female, but on some occasions, this phenomenon can be used to their advantage. With vertical maneuvering equipment, the user can escape from the Female Titan as other Titans consume its body, and the steam emitted from the continuously inflicted wounds can serve as a cover for the user if they do not desire to be seen.
The Female Titan is also known for its high endurance and mobility, the greatest instance of this being the journey to the Walls, where Annie Leonhart ran what can be deduced as near to the coastline of Paradis Island to the distant Walls, although this exhausted her to the point of resting in bed for several hours.
In addition to her Titan's scream ability, Annie Leonhart possessed the ability to harden her skin to diamond-like strength, able to shatter blades of ultrahard steel upon contact. She can also use this ability while coming out of her Titan's nape to create a diamond-like cocoon. Besides its defensive properties, Annie's hardening gives her melee attacks significantly stronger power, with a single well-placed blow being capable of dismembering or even decapitating an enemy Titan.
The Female Titan, like all the Nine Titans, was brought into the world after the death of Ymir Fritz. In the 1,700 years following her death, the Female Titan was held in the possession of one or several of the warring Eldian houses subservient to the Founding Titan. After these seventeen centuries when Karl Fritz, the 145th King of the Fritz family, abandoned the conflicts of Eldia and relocated to Paradis Island, the Female Titan was taken by the nation of Marley during the Great Titan War.
In the year 845, the nation of Marley sent out Annie, Reiner Braun, Bertolt Hoover, and Marcel Galliard across the ocean to Paradis Island as the start of the Paradis Island Operation. Her Female Titan was responsible for the massive amounts of Titans that invaded Wall Maria during its fall.
Five years later, Annie's Female Titan makes its first appearance in the Walls during the 57th Expedition Outside the Walls. With suspicions that Eren Yeager has inherited the Founding Titan by some means, the Warriors change their goal from wiping out the Eldians in the Walls to capturing Eren Yeager. Having heard of Eren's supposed position in the expedition from a fellow Warrior, Annie attacks the right flank of the formation first in search of Eren, taking precautions not to kill any soldier in the Survey Corps before seeing their face. With her Female Titan's ability, she gathers many Pure Titans following her trail which brings devastation on the right flank.
After venturing into the formation for some distance, Annie encounters Armin Arlert and corners him. For reasons she is uncertain of, she spares Armin's life and continues in her search for Eren. Armin pursues her with Reiner and Jean and informs them of his theory on Eren's position in the formation. As they engage the Female, Reiner pretends to get caught by her and uses the opportunity to carve directions to Eren's true location into the Female's hand. The Female Titan abandons her fight with the soldiers and changes her plan of attack.
When word reaches Commander Erwin Smith of the sudden attack on the right flank, he changes the direction of the expedition into a nearby Titan Forest where he and the veterans of the Survey Corps set a trap for the Female with the special target restraining weapon. The Female Titan enters the forest and soon comes across Eren in the Special Operations Squad led by Captain Levi. She pursues Squad Levi for some time, but is eventually caught in Erwin's trap.
With her Titan form totally restrained, Annie uses her hardening ability to protect her body from further harm. After overhearing plans to extract her from her nape, she makes use of the Female Titan's true ability and screams out for any Titans in the area to come to her. A horde of Titans from all directions soon answers her call and began to consume her Titan body, leaving the Survey Corps with no choice but to drive off the Titans. In the chaos, Annie escapes with the help of vertical maneuvering equipment and pursues Eren in her human form. After killing Gunther Schultz with her blades, she transforms into the Female Titan a second time and battles with Squad Levi. The Female Titan is briefly immobilized, but through prioritizing her healing she is able to kill Eld Jinn, Oluo Bozado, and Petra Ral.
With no one left at his side, Eren transforms into the Attack Titan and battles with the Female Titan. The two struggle for some time, but Eren is stunned in place upon recognizing a fighting stance used by Annie. In the moment, Annie incapacitates the Attack Titan and captures Eren. As she flees the forest, Mikasa Ackerman and Captain Levi pursue her and successfully immobilize the Female Titan, rescuing Eren. Defeated, Annie would no longer pursue Eren during the expedition.
Several days later, Annie is cornered by the Survey Corps in Stohess District thanks to Armin's suspicions of her identity as the Female Titan. With no hope for escape, she transforms into the Female one last time and attempts to escape, but Eren's Attack Titan pursues her. After a short skirmish, the Female incapacitates Eren and attempts to scale Wall Sheena, but Eren successfully tosses Mikasa up to her position where she cuts the fingers of the Female Titan, sending her falling to the ground. As the Attack Titan and the Survey Corps close in to extract Annie from the Female's nape, Annie resorts to using her Titan's hardening ability to encase herself in a crystal-like substance to prevent interrogation. Annie's crystal is later brought underground, the Female Titan rendered temporarily unusable.
When the Paradis Island Operation is postponed, the Warriors make no attempt to rescue Annie from her captors. Four years later, there is still no sign of the Female Titan's return. Zeke speculates it was either stolen or Annie is still alive since there has been no children discovered on the mainland with the Female Titan's power.
Somewhere underground in Paradis, Annie is shown to be still incapacitated within her crystal.