Warning: Spoilers ahead for Attack on Titans Chapter 137
In the latest chapter of humans who can voluntarily transform into a Titan. Further down the story, it's also revealed that there are nine of these special titans at a given point in time and that they've been ed from one Eldian to another for two millennia.
After defeating Zeke and taking control of the Colossal Titans within the walls of Paradis, Eren rallies them to literally trample the Earth flat, leaving only the Eldian people to walk on what's left of the Earth. Despite his arguably good cause for the Eldians, other Eldians, including his friends, are not sold into his plan. Instead, they want to rally and stop Eren no matter the cause. Within the group that is trying to stop him are part of the Nine Titans, so Eren has to come up with something to fight them. That happens to be summoning and using the previous versions of the Nine Titans like marionettes.
With Annie's Female Titan, Armin's Colossal Titan, Reiner's Armored Titan, and even Franco's Jaw Titan, they manage to put up a fight. Things, however, take a good turn when Armin gets eaten by one of the Titans. He manages to enter the world where Zeke is and have a little talk with him. He manages to convince Zeke not to give up just yet.
When the other wielder of the previous Nine Titans appear, they manage to convince them to fight for them and resist Eren. Of course, they aren't able to wake up those wielders they have no prior connection. This results in the previous generation of Nine Titans battling the more ancient ones. With the help of Bertolt, Ymir, and the others, they manage to issue a counterattack, which leads to Eren's possible demise.
With the manga ending this year, Attack on Titan is bound to put a conclusion on Eren's epic saga. The loose ends are now meticulously being knit together for better and for worse. With Eren's friends from the Survey Corps' final attack, fans might have just witnessed Eren's fated end. However, nothing is certain yet as nobody has been confirmed.
