Zeke Yeager

The Ape Titan (獣の巨人) is an unusual Titan that was first seen within Wall Rose during its supposed breach, and possible central antagonist in the overall series.

Story
The Ape Titan makes its first appearence in Chapter 35, when Titans are mysteriously appearing within Wall Rose even though the Wall remains intact. The Titan displays remarkable intelligence in its encounter with Mike Zakarius. It prevents his escape by killing his horse and ordering the other Titans not to eat him so that it can question him about the Three Dimensional Maneuver Gear. It takes Mike's gear for investigation when he neglects to respond.

The Ape Titan walks past Castle Utgard and starts to climb Wall Rose.

The Ape Titan breaks off chunks of the Wall Rose and throws them like missiles at members of the Survey Corps trapped in Castle Utgard. The first shot kills their horses, and the second kills Rene and Henning. Afterward, it summons more Titans to resume the attack on Castle Utgard, seemingly toying with the soldiers trapped inside.

The Ape Titan is said by Ymir to be directly responsible for the appearance of Titans within Wall Rose, possibly in order to "test" humanity's strength. She reveals that locating it was one of Reiner and Bertholdt's primary goals and is key for them to return to their village.

Trivia

 * The Ape Titan 's appearance resembles the form of a cryptid known as Yeti or Bigfoot.
 * It is hinted, but unconfirmed, that it has some method of transforming humans into Titans. The people from Connie Springer's village appear to have been victims of this, and were unique in their ability to function at night. The titans that attacked could have been the people in Connie's village since it is said that they didn't escape because of the horses still being there and since there wasn't a breach in the wall.
 * It appears to have had limited or no contact with humanity for at least half a century, as it expresses interest in humanity's 3DMG, and its unclear of whether Mike and it spoke the same language, however the latter may have been mockery since Mike was too nervous to speak.
 * The Ape Titan may be a reference to the Norse Beast Giant Gudmundr as in the Myth it resides in Warrior's Paradise" implying a connection to Reiner and Bertolt who consider themselves Warriors.
 * The Ape Titan is the first truly intelligent Titan to make an appearance. Most other Titans possessing intelligence are Titan Shifters, who are controlled by humans.