Titans greatly resemble human beings in that 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 are masculine, although all Titans lack sex organs- their method of reproduction is currently unknown. Titans almost universally possess widened mouths with an enormous number of small, square teeth. They apparently lack canines, although possibly not incisors, and use these in their primary activity – eating humans. They apparently do not possess a complete or functioning digestive tract, merely a stomach-like cavity that eventually fills up with what they swallow, forcing them to regurgitate in time to continue eating more humans they encounter.
Titans are compelled to seek out and devour humans for reasons 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 what passes for its stomach with dead humans, it regurgitates them 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 forms of life.
Most Titans are not very intelligent and many are little more than mindless beasts, easy to trick, distract or deceive.