Mikasa Ackerman.

For hundreds of years, the world was inhabited by terrifying monsters of enormous size, which were called Titans, and for the survival of humanity, three large walls were erected - Maria, Rose and Shiganshina.

They were somehow able to hold off the Titans and separated three small cities. This small state was ruled by a king and a handful of his accomplices. However, even this wasn't enough. The Survey Corps was founded—an organization of well-trained soldiers who would raid the walls and seek a way to rid the world of Titans by gathering information about them and exterminating them. It had existed for many years. It was led by commanders-in-chief who changed time after time, year after year... At the moment, that commander was Erwin Smith. Hundreds, if not thousands, of people joined it to give their hearts for humanity, many died. But as Smith himself said, "Without sacrifice, there is no victory."

There was also the military police—a guard that remained within the walls, close to the king. It was mostly recruited by those seeking security and a good salary.

To combat Titans, humans also invented the SMUD (Spatial Maneuvering Device), a specialized piece of equipment used by Survey Corps soldiers to combat Titans. Its primary purpose is to grant the soldier incredible mobility: using harpoon grapples and a gas-powered mechanism, it can cling to objects (walls, trees, ledges) and quickly move through three-dimensional space. The goal of these maneuvers is to reach the Titan's weak point (the base of the neck) and deliver a decisive blow. What does the SMUD consist of?
tight belts that wrap around the body;
handles (they also serve as hilts for swords);
harpoon grips;
gas mechanism (compressed gas in cylinders activates the firing system and cable rewinding);
a mechanism for winding the cable (often in the form of a turbine rotated by compressed gas).

The Intelligence Corps was located in various headquarters, training grounds and other buildings that were scattered throughout the walls and even beyond them.

Mikasa Ackerman is the adoptive sister of Eren Yeager and one of humanity's strongest fighters.

Appearance
Facial features and appearance: Mikasa has Asian features, fair skin, and gray eyes. She has a small scar under her right eye; she received it during the Battle of Trost, when Eren, in his Titan form, accidentally grazed her.
Hair: Black, length varies over time. At the beginning of the story, her hair is longer, but she later shortens it for battle comfort. By 854, her hairstyle becomes more tousled, with a longer front.
Build: Tall (176 cm), slim, but very muscular - her physical strength makes her stand out from the other fighters.
Clothing and recognizable details: standard Survey Corps uniform (white shirt, equipment), green cape with the corps' insignia. The main detail of her look is the dark red scarf Eren gave her after rescuing her as a child; Mikasa almost never takes it off.

Character and personality
Before the tragedy that took the lives of her parents, Mikasa was a cheerful, sociable, and insightful child. However, after a group of kidnappers murdered her parents before her eyes, her worldview changed dramatically. To survive and protect Eren, Mikasa was forced to make a radical decision and fight the attackers. This experience left her more emotionally reserved and withdrawn, but she retained a deep attachment to her loved ones—Eren Yeager. Age 16-17.

Eren Yeager is a young man of average height with a muscular build. He has gray-brown hair and turquoise eyes. His face is slightly tanned, with rounded features. His hair is cut short. His typical appearance is a Survey Corps uniform with the "Wings of Freedom" emblem, often with the top unbuttoned and the cape flowing.

Character and motivation
Since childhood, Eren has been obsessed with the idea of ​​escaping the confines of his walls and seeing the world: a friend gave him this dream when he showed him a forbidden book about the outside world. He's quick-tempered, straightforward, intolerant of injustice, and ready to rush into battle without regard for the consequences. At the same time, he's sincerely devoted to those close to him—especially Mikasa—and is willing to make extreme sacrifices for her.

Important connections
Mikasa Ackerman. Eren shares a deep bond with her: he saved her as a child, and they grew up as a family. Their relationship is both a source of support and a source of internal conflict for Eren. They are approximately 16 years old.