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Titans (巨人 Kyojin?, lit. "Giant") are the primary antagonists and serve as the primary catalyst in the events of the Attack on Titan series. They are a race of giant humanoids that were thought to have first appeared 107 years ago and rapidly exterminated humanity to the point of near-extinction. In reality, the Titans are transformed humans from an unknown land outside the Walls.
Titans greatly resemble nude human beings. They are bipedal creatures with the same number and arrangement of limbs and features one would expect in human beings. They are all deformed by human standards to a greater or lesser degree, ranging from minor abnormalities in proportions (enlarged head, small limbs, etc.) to apparently lacking skin and subcutaneous tissues, although they do not bleed from such deformities, indicating that they perhaps possess some other mechanism to compensate for this. The vast majority of Titans have a masculine body shape, although all of them lack reproductive organs.
Titans, almost universally, have exceptionally wide mouths with an enormous number of small, square teeth. Although some only possess canines, a majority of Titans lack them. In all likelihood, they have and use incisors for their primary activity: eating humans. Titans do not possess a complete or functioning digestive tract, and merely have a stomach-like cavity that eventually fills up with what they swallow. After consuming a certain amount, they would be forced to regurgitate and empty out the cavity before they can eat more humans.
Titans are compelled to seek out and devour humans for reasons currently unknown, as they do not derive any real sustenance from them; they did not taste human flesh for nearly a century after the Walls went up, but this did not affect their activity or numbers. It should also be noted that once a Titan has filled up its stomach-like organ with dead humans, it regurgitates them in a giant ball and continues eating more as soon as possible.
It should be noted, as mentioned above, that Titans eat humans for no other apparent purpose than killing them. They ignore all other animals and any non-human forms of life.
Most Titans are unintelligent and simply mindless beasts; easy to trick, distract, or deceive. The wielders of the power of the Titans are the exception: They have human level intellect due to being piloted by a human. However, some Abnormals are also able to sustain some of their former intelligence, such as the Titan encountered by Ilse Langnar and Conny's mother. These Titans can form thoughts and even communicate with humans.
The most dangerous aspect of the Titans is their unpredictability. They do not follow a strict set of rules and have displayed additional anomalies. After the supposed breach of Wall Rose, Titans are seen moving in the dead of night when they should be inactive.
Titans are human in nature. It is unknown how the very first Titans came to be. People are able to turn into Titans after being injected with a Titan injection, triggering a transformation from human form into Titan form. The time between the injection and transformation is very brief, though not instantaneous. Titans often bear a strong resemblance to their original human bodies, though women who are turned into Titans lose any feminine body features.
The Titans' body structure and power source are very mysterious and they apparently violate several known laws of science, seemingly capable of spontaneously generating both energy and mass. Their extremely high level of activity and body temperature indicates the need for a massive intake of energy to fuel them, yet they apparently never need to eat at all. They possess vocal organs and are able to emit simple sounds like roars and screams, yet they apparently do not need to breathe. They do seem to become less active at night or if deprived of sunlight, and so it may be possible they draw their primary source of energy from the sun. Individual Titans seem to possess varying levels of stamina once deprived of sunlight; the captured Titan 'Sawney' became docile and nearly comatose after only an hour's deprivation, while fellow captive 'Beane' maintained a high level of activity three hours after last seeing sunlight.
Titans' bodies also seem unusually light for such large creatures - a severed arm is described as weighing almost nothing, and they are able to move at high speeds despite their size. Due to their size, Titans possess enormous strength and when combined with this lightness, they can put on amazing bursts of speed and agility.
In addition to their size, speed, strength and large numbers, Titans also possess incredible regenerative abilities. The only sure-fire way to kill them (known to date) is by slicing out the nape of the back of the neck measuring 1 meter high and 10 cm across. They regenerate lost and damaged body parts within seconds to minutes, including severed heads (although, there are rare instances where the head will not regenerate if the nape is cut through or blown off). It should be noted that the vulnerable area is where the real human body would be for shape-shifting Titans, as proven by Eren Jaeger. When struck at this site, the human controlling the Titan (or rather, what remains of them) is decapitated, killing both. After death, Titan corpses rapidly evaporate to skeletal remains, then to nothing at all.
How Titans react to pain stimuli varies from one to another. Many Titans will utterly ignore injuries which would be agonizingly painful to a human, such as losing limbs, being impaled through the heart, or having their eyes gouged out (even if such injuries will soon regenerate). In combat, some Titans will completely ignore armed humans who are attacking them, and simply proceed to attempt to eat whichever human is closest to them. Others seem vaguely aware of humans who are attacking them, and if injured will have a reaction that might be pain but more accurately seems like simple annoyance. Some actually do seem to react in pain and shout when they are injured. In Hange's experiments, Beane shrieked in pain when they gouged out its eyes with a heated metal spear, but Sawney seemed oblivious to the fact that Hange had impaled it through the heart region using a spear.
Types of Titans
Titans are classified according to their size and abilities. The following is a list of various known Titans so far in the series.
| Ranging from 3-15 meters in height, these Titans compose the vast majority and are very variable. They all resemble humans but with lesser to greater deformities, some of them walk on two feet while others walk on all fours. They are also variable in regards of their level of activity and response to pain. Their only common feature is their mindless nature. They would always head towards the first human on sight, without further planning or reasoning, making them easy to deceive and lure into traps. However, they are still dangerous due to their sizes, physical strength and numbers.
Notable Titans of this type:
|Any Pure Titan that displays abnormal behavior or intelligence is classed as an Abnormal. Unlike most Titans which mindlessly attack and devour humans on sight, Abnormals often ignore nearby humans and charge to more important locations where they can do more damage. Some Abnormal Titans possess noticeable physical deformations, such as lacking skin in certain areas or carrying less weight than others.
Notable Titans of this type:
There are some humans capable of transforming into Titans who have various unusual traits and skills that can be honed and directed with purpose. These Titans are usually stronger and/or faster than typical ones and retain their intelligence during a controlled transformation. They generally do not have any deformations that hinder their skills, and often resemble their human "pilot." A skilled human with the power of the Titans can move more quickly and regenerate parts of their body just by focusing, and even discard their body entirely and regain a new Titan form within minutes.
Notable Titans of this type:
- Some Titans are modeled after friends and acquaintances of Hajime Isayama. Sometimes, he will even take requests.
- In the August 2016 Issue of Bessatsu Shonen Magazine, Isayama was asked of what is it like to come out of a Titan's body. He stated, "Just think that it’s like coming out from a sauna."
- While many Titans have a masculine appearance, some Titans seen have had feminine facial features although retained a masculine body shape.