Wall Titan

The Wall Titans are an unusual kind of Titan that make up the walls that protect humanity. They were first revealed when the Female Titan tried to climb Wall Sina to escape from Eren Yeager. The lack of sunlight inside the walls renders them immobile.

Appearance
The Wall Titans are similar in appearance to the Colossal Titan, in that both their surfaces are covered in primarily muscle tissue. Their exact height is not known, but seeing as they make up the walls, they must be extremely tall.

History
The Wall Titans are enveloped in mystery. Nothing about their history is known so far. Questions like where they come from and what their motives are are yet to be answered.

Abilities
It is implied that the Wall Titans have the ability of using their crystallising powers to create massive walls, notably Wall Maria, Rose and Sina. Their exact motives for doing this are not known at the moment. When sunlight is not available, the Wall Titans are incapable of moving. When exposed to sunlight, they are able to move, but because this hasn't happened, the other abilities that they may possess are not known.