The Colossus Titan was one of the Nine Titans and the early main antagonist of the Attack on Titan series. It was notable for its incredible size and its ability to control both the steam emitted by its Titan body and the amount of energy released during its transformations.
Abilities: Although all Titans generated enormous amounts of heat and energy during transformation, the users of the Colossus Titan could control the energy they produced to create various effects. For instance, when Bertolt Hoover attacked Trost District his transformation only causes a wind blast that knocked some trainees over the Wall. However, during the Battle of Shiganshina District, Bertolt released a much larger explosion, creating a mushroom cloud of dust and rubble, ravaging part of the city, and instantly killing a great number of Survey Corps soldiers.
History: The Colossus Titan, like all the Nine Titans, was brought into the world after the death of Ymir Fritz. In the 1,700 years following her death, the Colossus Titan was held in the possession of one or several of the warring Eldian houses subservient to the Founding Titan. After these seventeen centuries when Karl Fritz, the 145th King of the Fritz family, abandoned the conflicts of Eldia and relocated to Paradis Island, the Colossus Titan was taken by the nation of Marley during the Great Titan War.
Story: Bertolt transformed into the Colossus Titan outside the southern gate of Shiganshina District, the southernmost territory of Eldia. Using his immense size, Bertolt's Colossus Titan breached Wall Maria in one kick, allowing for the many Titans awaiting outside to enter into Eldia's territory. Bertolt joined his fellow surviving Warriors and entering the walled territory during the chaos.
Trivia: The Colossus Titan ranked 1st on the Titan Popularity Poll. The Los Angeles Dodgers pitcher Kenta Maeda has a baseball glove designed after the Colossus Titan. Since its first appearance, Bertolt's Colossus Titan has become one of the most recognizable and iconic images of the Attack on Titan franchise as a whole.
Source: Colossus Titan, available under CC BY-SA 3.0.