Chapter 78 of "Attack on Titan" is available for online readers at My Manga. Before any spoilers and predictions, here's the recap of the latest chapter.
With Bertholdt flung inside the walls, the Survey Corps retreat to avoid his blast. However, he hesitated in transforming as a titan after he saw Reiner incapacitated. He opted to be with him instead of attacking. He discovered that while Reiner is incapacitated and appeared dead, he is still alive by transferring his consciousness to his nervous system.
Meanwhile, the Survey Corps realizes that Bertholdt is not transforming and sees this as a chance for attack. They immediately saw Bertholdt coming for them in human form.
The Survey Corps broke into two: Hange's Squad and Levi's Squad. Hange's Squad left to check on Reiner while Levi's Squad remains where Armin decides to talk to Bertholdt for a possible negotiation.
Bertholdt is against any form of negotiations and reveals that he has plans to destroy humanity and he's no longer the person they used to know.
While Armin and Bertholdt talk up close, Mikasa tries to attack from behind. Bertholt dodges the attack and leaves so he could go back to Reiner.
Hange's Squad has arrived to finish off Reiner. However, they discover that Reiner has moved and his position has made it difficult for the team to finish him off. They then saw Bertholdt on top of them where they realize he is about to transform.
They try to run away from the blast caused by transformation. Levi's Squad looks on the blast and realizes that there could be no survivors.
The Colossal Titan has finally revealed himself inside the walls. It's very likely that the next chapter would feature some form of confrontation between Eren and the Colossal Titan. However, help should arrive because of their limited numbers.
Forum users at Manga Helpers speculate that Historia Reiss might come to their aid not only to help them as a member of the Survey Corps but also to help Reiner recover his memory. Reddit users on the latest chapter also speculate that someone could have survived the blast who could also aid in the fight against the Colossal Titan.
