|Former Affiliation||104th Trainees Squad|
|Manga||Ch.2 On That Day|
|Anime||Ep.2 That Day|
Annie is considered a solitary, stoic type and friendships don't come easily. She is apathetic and somnolent with little desire to put in any effort into meaningless disciplines or activities, and instead focuses exclusively on making it into the Military Police to obtain an easy life. Yet, somehow she does seem to hold some strange fascination with people that hold a deep sense of duty and righteousness -- in those people who do care and who can devote their lives and even die for causes.
Originally from the same village as Reiner Braun and Bertholdt Fubar, Annie had rigorously trained with her father ever since she was young. During a flashback, her father begged for forgiveness, for the harsh way he trained her. Thinking it may be too late, he tells Annie to treat everyone as her enemy and she promises to come home to him. 
Graduating 4th, a rank below Bertholdt Fubar, Annie choose to enlist in the Military Police. When the Colossal Titan breached Wall Rose, the same way it did with Wall Maria, Annie was assigned to rear guard with Mikasa and a few of the others to help fend off the Titans as the people are evacuated to the safety of Wall Shina. She was involved in helping Jean Kirschtein and the other retake the supply unit to restock the gas canisters for their gear. While watching Titan Eren fight off the other titans, Annie overhears Jean and Reiner arguing and so she think that he may be their ally. She learns about Eren's shapeshifting ability.
During hand-to-hand combat training, Annie easily bests Eren and Reiner with a kicking technique her father taught her. Later on during dinner, she watched as he used the same technique to subdue Jean when he tried to pick a fight again. The next day, Annie and Eren were watching him as he practice hand-to-hand combat. She noticed that Jean's only taking it seriously just to pick a fight again and doesn't see anything positive from it. Annie points out something wrong in how Eren handled the kicking technique and offers to teach him the proper techniques. 
Soon the two titans captured for research are killed and the Military Police check the Three Dimensional Maneuver Gears from the trainees. During that time, Armin, Annie and Conny Springer discussed which military branch they want to join. When Annie reveals that she will go to the military police, Conny considers joining them too and asks for her opinion. Annie responds telling him that it's his decision to make, not hers. When she learns Armin plans to join the Scouting Legion, she asks him what he would do if he was ordered to die. He tells her if the reasons are good, then he'll do so. Annie thinks he's weak physically, but yet he's very strong at heart. Later we learn that she offered Marco Bodt's 3DMG for inspection as her own, and that prompted Armin to become suspicious of her. Ultimately during the Scouting Legion draft, Annie leaves to join the military police.
Arc 2: Annie VS MikasaEdit
Annie awakens in her room in the Stohess District of Wall Shina. Her hair is the same as the Female Titan's when not tied up in a bun. Annie is teased by Hitch and Marlo, but a member tells them to leave her alone believing that she hasn't recovered from battle and is the only one who has real combat experience. Soon Armin approaches her and asks for help in hiding Eren until they can convince the king to better protect the walls. Annie reluctantly agrees by putting on her father's ring and escorts them to a place where they can hide. When Eren and Armin try to get her to go down an underground passageway with them, she refuses and suspects something is awry. Mikasa, having enough of Annie's games, takes off her hood and draws out her 3DMG. She refers to her as the female type titan. Armin's suspicion is confirmed when she smiles in the same way as the female titan, and by her refusal to enter the passage, where she cannot transform. 
After firing a signal, disguised recon corps comes out of their hiding places and try to restrain Annie. Seeming captured, she is still able with a flick of her thumb to open a small blade hidden in her father's ring and prick herself, thereby allowing her to transform into her titan form and kill those restraining her. Now, resuming her attempts to capture Eren, Armin and Mikasa realizes how desperate she is and try to get him to fight her. Overcoming his initial shock at the identity of the female titan, he transforms into his titan form and takes Annie on. 
As Eren tries to hold Annie off from escaping, Mikasa realizes that she may be the only one who can stop her. Knowing that she may try to climb the wall to get out of Wall Shina, she trails Annie. Annie decides to fight and defeat Eren again. After that, she continues to try and escape. However, by that time, Mikasa had already caught up to her climbing the wall. Not hesitating in the slightest, she cuts off all of Titan Annie's fingers, leaving her struggling to hold on. Mikasa then tells her to fall down and pushes her off via the head. Eren in his titan form hold down the body as both the military police and the members of the Scouting Legion, cut into the flesh and try to extract Annie. 
When Annie is trapped inside a crystal, while one of the Scouting Legion members tries to break the crystal to extract her, but Hanji stops him and tells both the Military Police and the rest of the Scouting Legion to take her underground and detain her. Meanwhile, Jean who went into the town supposedly posing as Eren learns the truth about Annie being the female titan.
Ultimately, Annie has been desperate to kidnap Eren and reasons for that remain unknown. 
Annie is one of the strongest fighters alongside Mikasa and Eren. She was ranked as one of the top 5 trainees at 4th position, implying a degree of skill in other military combat forms such as the use of 3D Gear.
Like Eren, Annie displays an ability to transform into a 14 meter titan. She uses this form to wipe out military formations the Scouting Legion uses during their attempt to retake Wall Maria. Annie's titan form is similar to Eren's form, but more feminine and muscular.
It is unknown how Annie seems to know the secrets of transforming into a titan and to be so adept in using her titan powers. She is far more experienced in using her titan form compared to Eren, who had only discovered his titan powers recently. She is probably the most skillfull user of titan powers among all current known titan shifters, sporting a variety of presumably learned powers not exhibited by any other titan shifters.
In her titan form, she is able to selectively regenerate certain parts quickly as opposed to automatic simultaneous regeneration of all the damaged parts. She can selectively harden parts of her skin to protect it from damage or to enhance attack, and also shout to attract attentions of regular titans, seemingly being able to deliver simple orders while she is at it. Unlike most titan shifters who tire to the point of collapsing, she is able to preserve stamina and is fit enough to utilize the 3DMG to kill experienced soldiers before transforming for the second time - something never seen done by any known titan shifters thus far. Upon capture and extraction, she is able to generate a cocoon of incredibly hard and durable crystal, something that no known technology can yet break into, to trap herself in so as to avoid being interrogated.
Being trained as a child by her father, Annie has shown to be adept in various martial arts such as Muay Thai, being her primary form of stand up striking. One such move was a kicking technique that she used to defeat Eren and Reiner during training. She also has skill in Brazilian jiu-jitsu which she showed when defeating Eren in past spars and taught him various chokes and locks, which he would also apply effectively against Reiner. As such, she had proven herself to be the top hand-to-hand fighter among the recruits. This gives her a massive advantage in combat in her Titan form, as she combines her extensive hand-to-hand combat skills with the incredible abilities of her 14m Titan form.
Annie Leonhardt's Statistics:
- In episode 2 of the anime, you could spot Annie in front of the line to receive her bread rations. A scene that was not visible in the manga.
- It is implied that Annie and Mina Carolina were close friends.