In Attack on Titan, monsters known as Titans plague the world as they constantly attempt to devour people; however, as Season 2 and 3 revealed, Titans are humans who are forcibly changed into these monsters and there is a world beyond the walls that believe those within the walls, Eldians, are devils who should be exterminated. In order to assure the downfall of Eldians, several people from the outside world are sent to the Eldia to obtain the Founding Titan and eliminate life in the walls.
These people have the ability to shift into enhanced titans, and they not only maintain their memories while in their Titan form but they also have abilities that supersede the abilities of regular titans. One of these shifters, Annie Leonhart, is the primary antagonist of Season 1 and her titan, the Female Titan, poses a real threat due to her unique anatomy.
High Mobility and Endurance
Throughout the series, it's commonly known that - due to their disproportionate bodies - most Titans have poor mobility and endurance, moving slowly and often having rag doll-like limbs. While there are a few anomalies that will run to catch their prey, even their speed is nothing compared to that of the Female Titan's.
Annie's speed and endurance allow her to not only easily outrun other Titans and evade the Scout Regiment, but it also means she can travel for long periods of time across huge distances, as seen in her pursuit of Eren Yeager beyond the walls in Season 1 Episodes 17-22. Another benefit of this form is, unlike other Titans, the Female Titan has full control of her mobility, which allows her to jump, dodge attacks and square off in a fight, as she did with much success against the Scouts and Levi's Squad, killing dozens of them in the process. Since Annie is also one of the best hand to hand fighters in the show, her technique and skills are translated perfectly to her Titan form, and her Female Titan is able to hold her own and often win the fight, as she did against Eren's Attack Titan in Season 1 Episode 21.
Control of Healing Factor
Another universal trait for Titans is their ability to heal wounds and regenerate limbs. This usually takes some time, but the Female Titan can channel her energy into which areas of her body need to heal first. This is demonstrated in Season 1 Episode 21, where Annie focuses her healing on her eye so she is able to see the members of Levi Squad, taking them by surprise and killing every member except Eren and Levi.
It also appears that, along with being able to heal desired areas first, the Female Titan is amazingly resilient against damage. Despite suffering a crushed skull and severed leg in Season 1 and Episode 25, Annie is able to continue her attempt to escape over the wall up until Mikasa chops off her fingers so she can no longer climb. This could be attributed to her Titan anatomy but also to Annie's inner drive to finish her mission and return home.
Enhanced Vocal Chords
While Titans are unable to speak - with some exceptions - and they rarely make a sound, several of the Titan Shifters have shown they can. Ymir's Jaw Titan, Zeke's Beast Titan and Pieck's Cart Titan have all spoken in the anime, and while Annie's Female Titan, like her human self, is not talkative, she does have a gift with her vocal chords.
In Season 1 Episode 20, after being caught by the Scouts and having Levi threaten to take her apart piece by piece, Annie lets out a horrific scream that rings beyond the miles of forest. Shaking the trees, this roar draws every Titan in the vicinity to her location. Surprisingly, the roar also temporarily hinders the Titans' desire to eat humans and they instead focus on consuming the Female Titan.
Selective Hardening
All Titans have thick skin that requires a special blade to cut through it, but the Female Titan's anatomy has an extra defense. She can select parts of her body to harden into an impenetrable crystal, and while it's established in Season 2 that Eren's titan can also do this, Annie has full control of this ability. She first demonstrates it in Season 1 Episode 21, when she hardens the nape of her neck to protect herself from Oluo Bozado's blade.
Along with being an excellent defense, her crystal ability is great for offensive moves. When fighting Eren in the woods, she crystalizes her fist, creating makeshift brass knuckles and ripping Eren's jaw off in the process. She can also use her ability to make her fingers into a set of claws, which came in handy when she attempted to scale the walls.
Crystal Defense
Aside from using her crystal abilities as the Female Titan, Annie can also use them in her human form. When it looks like all hope is lost for Annie and Eren is about to devour her after their battle in Season 1 Episode 25, she generates a crystal cocoon around herself.
Annie, who's already demonstrated that she has no interest in cooperating with the Scouts, puts herself in a coma like state so she is physically unable to comply or answer any of their questions. The cocoon also allows her to rest safely since nothing can penetrate the crystal shell, so threats of torture are nonexistent. In the anime, she is still in the cocoon and the extent of this skill remains mysterious, though recent manga chapters expand on this Titan ability. With Season 4 - the final season - airing this fall, these abilities as well as Annie's fate will be revealed for those who only watch the show.
