|It's a threat to all of humanity! Swarm the huge bastard!|
|— Hange Zoë leads an attack on the Colossal Titan|
The Colossal Titan (超大型巨人 Chō ōgata Kyojin?) is the Titan form of Bertholdt Hoover and humanity's greatest threat. It first appeared five years ago during the fall of Wall Maria and returned five years later at Trost.
The unique ability possessed by the Colossal Titan appears to be significant control over the amounts of steam emitted by the Titan form. In normal circumstances, Titans emit steam from wounds, and their bodies evaporate completely into steam after receiving a killing blow. The Colossal Titan is capable of emitting great amounts of steam at will. This power can be used for a variety of purposes. By emitting great amounts of steam at once, the pressure and force of the steam will burn and repel any individuals in close proximity to the Colossal Titan that are not fixed in place.
However, prolonged use of this ability takes a toll on the Titan, decreasing muscle mass gradually until only the skeletal structure remains. In some cases when it is necessary, the Colossus Titan is capable of evaporating its entire body at once, disappearing instantly. This puts the user in a position of great vulnerability, with no way of preventing a fall from a great height where the Titan form once was. However, this disadvantage can be alleviated if the user is wearing ODM gear.
The Colossal Titan is infamous for its incredible size, standing at a previously unseen 60 meters, high enough to peer over the top of the Walls.
The Colossal Titan makes its first appearance outside Wall Maria, terrorizing the population of Shiganshina and kicking a hole in the southern gate. Soon afterwards, the Titan inexplicably disappears in a cloud of steam. Its actions allow the normal Titans wandering outside to enter Shiganshina, where they begin to feast on its many inhabitants, including Carla Jaeger.
The Colossal Titan reappears five years later in the year 850, breaching Wall Rose so that its brethren can once again devour the humans inside. It is almost immediately attacked by Eren Jaeger, but it first repels and blinds him with vapor from his high-temperature body before vanishing completely from view as it did five years before. This attack prompts the Garrison to enact the Colossal Titan contingency plan for Trost District.Reiner, in a moment of exhaustion and desperation, reveals himself to be the Armored Titan and exposes Bertholdt as the Colossal Titan, the two transform into their Titan forms and battle against the Scout Regiment.
As Reiner's Armored Titan battles Eren's Titan, Bertholdt fights against the Scouts with a partially transformed Colossal Titan. When the soldiers are ready to land a killing blow, Bertholdt once more uses his steam emission control to keep them all at a distance, and their ODM gear is unable to reach him in the continuous gusts of wind. Bertholdt's Colossal remains in this state of emission for a short time until Reiner faces imminent defeat in his struggle against Eren and calls for help. Hearing Reiner's signal, Bertholdt falls to the ground below. This causes a destructive explosion below, with the Colossal Titan evaporating into a gush of steam. Bertholdt leaves his Titan, and joins up with Reiner, who had managed to capture Eren in the chaos.