Attack on Titan's manga is, without a doubt, laying the groundwork for the series' big finale as the latest chapters of the series have sparked a major (seemingly final) confrontation between the Eldians, Marleyans, and Yeagerists. Zeke and Eren are closer than ever to enacting their terrible plans, and one major attack has been lying in wait for Zeke to get desperate enough to use. While fans have seen Zeke enact cold-blooded plans before, the latest chapter of the series takes it up a notch.
In Chapter 119 of the series, Zeke finally acts out his major plan of using his Beast Titan yell to activate the spinal fluid many people had drank and summon a whole new army of Titans. But before he does this, Zeke turns down Colt's pleas to hold off turning his younger brother Falco into a Titan.
It was revealed in a previous chapter that Zeke had slipped his spinal fluid into a wine shipment, and many people across Eldia had mistakenly drank the polluted wine. This was a ploy meant to have an army of Titans at his disposal whenever he needed, and he definitely needed it in Chapter 119 as Marley's counterattack had left him pinned down and left without any option.
When Zeke tells Eren he's going to activate the Titans, Colt surprisingly runs to his side and begs Zeke to wait. He tells Zeke that Falco drank some of the wine, and Colt hopes to speak to Zeke's "humanity" as the Zeke he knew wouldn't want children to be victims. He wanted Zeke to wait until he got his younger brother out of the range of the scream, and Zeke pauses for a moment.
Zeke tells Colt that he sympathizes with the fact that he cares for his younger brother, and apologizes, but activates his scream anyway. This leads to the death of Colt, Falco and numerous others becoming Titans, and the resulting chaos even leads to a new Jaw Titan emerging. Zeke and Eren are on a whole new wavelength in this final arc of the series, and this is only the latest sin on his slate, but now it's clear that there's going to be nothing holding them back now.
Attack on Titan was originally created by Hajime Isayama, and the series has since been collected into 23 volumes as of 2017. It's set in a world where the last remnants of humanity live within a walled city in order to escape the danger of the Titans, a race of giants monsters that eats humans. The lead character, Eren Yeager, ends up joining the military with his two childhood friends Mikasa and Armin after the Titans break through the wall and attack his hometown. Now Eren, Mikasa, and Armin must survive in a world where they not only have the Titans to fear, but the very humans they are trying to save. You can currently find the series streaming on Crunchyroll, Funimation, and Saturday nights on Adult Swim's Toonami block.