WARNING: The following contains spoilers for Kaiju No.8, Chapter #32, by Naoya Matsumoto, David Evelyn, and Brandon Bovia, available in English from Viz Media.
Keeping a secret identity is a commonly used trope in comics to create dramatic tension, with the reveal of said secret often presented as a major plot point. These storylines can often go on for years if not decades. For example, Detective Conan has used the same secret identity plotline for almost three decades. So, when Kafka revealed his secret identity as Kaiju No. 8 in Chapter #32 of Kaiju No. 8, it caught many by surprise, opening up tons of new possibilities for the manga's future.
In the latest arc, a group of pterosaur Kaijus lead by an intelligent humanoid Kaiju have attacked the base of the Third Division. It takes a team-up between Vice-Captain Hoshina and Captain Ashiro to finally take the humanoid down. But before it died, the humanoid called up a giant yoju bomb capable of destroying everyone on the ground. Kafka had to transform into Kaiju No. 8 to stop the bomb, but this also meant exposing his monster form to everyone in the Third Division. Right before the end of Chapter #32, Captain Ashiro holds Kafka at gunpoint, ready to take him into custody.
Though everyone expected Kafka to reveal his identity at some point in the manga, no one expected it to happen this early on in the story, since Kafka had only just joined the JDF and became an official troop member less than ten chapters ago. He’s only starting to develop a relationship with most characters in the Third Division. The reveal of his identity will fundamentally change everyone’s perception of him, and his post in the Third Division should be essentially over.
With this reveal, the story could go in several directions. First, Kafka could run away as he did in earlier chapters. But as he noted in Chapter #32, his arms and legs are busted from punching away the bomb, so he may not even have the strength to run. Even if he did, now that everyone knows his real identity, it would be easy to catch him, unless he has some help from the inside. Ichikawa and Shinomiya are the obvious candidates for helping him out, but they may be too low in rank to really make a difference.
The second possibility is the most likely one: Kafka lets Captain Ashiro take him into custody since he still trusts her, seems to have thought about the consequences of his actions before he transformed. The question is what would the JDF do to him once he surrenders -- will he be interrogated? Experimented on? But these options seem like a waste of his potential as a powerful Kaiju.
Another likely scenario is that Kafka is recruited back into the JDF as a Kaiju to fight alongside the Third Division again. But this time, the Third Division would also be keeping an eye on him, ready to take him down if he ever loses control. This would keep the already established characters and relationships intact and the story moving forward without too much disruption, only with more added tensions and distrust. However, this has the added con of taking away from Kafka's original goal of contributing on his own strength, without his kaiju form.
Finally, it is possible that the entire Third Division could decide to keep his existence a secret and use his strength stealthily, without the top brass’ knowledge, because he just saved everyone's life. This seems unlikely given Ashiro’s honest and straightforward personality, though never discount the power of friendship in an action shonen manga.
No matter which direction the manga decides to take, this reveal definitely presents very exciting prospects for the future of Kaiju No. 8. Now that the secret identity plotline is concluded, new relationships will be forged, and more secrets about the Kaiju and their intentions can be uncovered with the help of Kafka.