The Eldian euthanasia plan, founded upon the power of the Founding Titan, was proposed by the Beast Titan's host, Zeke Yeager, inspired by his predecessor, Ksaver.
Its general outline was as follows:
First, obtain the power of the Founding Titan. Through its strength, alter the bloodline of all Eldians in the world, stripping every Eldian of the ability to reproduce, ensuring that no new Eldian children would ever be born in the future.
Second, although removing the reproductive ability of the Eldians, preserve the reproductive ability of certain royal-blooded Eldians capable of wielding the Founding Titan's power, ensuring the continuation of that power.
Third, through the Founding Titan's power, control the hundreds of thousands of Colossal Pure Titans that formed the three walls on Paradis Island, using them as necessary deterrence against the outside world. The Rumbling could be partially activated to demonstrate strength if needed.
Fourth, make full use of the time gained during the Rumbling's deterrence to vigorously develop technology, uniting with any other nations in the world willing to cooperate in scientific advancement. The nation of Hizuru had even promised to provide full support.
Fifth, the Marleyan Volunteers would fully take over Paradis Island. After the Eldians lost their ability to reproduce, they would inherit the name of Eldia. Once the last Eldian died of old age, a new Eldian Empire formed by the Marleyan Volunteers would emerge.
Sixth, all Eldians would disappear from this world. The name of "devil" would fade from history with the passing of the final Eldian. No new Eldian life would ever be born again, and no life would enter this world branded a devil from birth. Only the new Eldian Empire that inherited the name would remain. As for the royal-blooded Eldians responsible for passing on the Founding Titan's power, they too would gradually "disappear" from the future world.
The euthanasia plan was Zeke's lifelong goal and pursuit. In his heart, only this could free the Eldians from the devil's name they had borne for a hundred years.
The sins of the Eldians would no longer be passed down.
Zeke raised his head. He saw Mr. Ksaver. He was almost like half a father to him. When Zeke had struggled desperately under the dual pressure of his father Grisha and his mother Dina, striving for their so-called restoration of the Eldian Empire, it was Ksaver who had brought him a sliver of warmth.
Ksaver taught Zeke to play baseball, passed on all his lifelong research about Titans to him, and when his parents' Eldian Restorationists were on the verge of being exposed, it was Ksaver who advised Zeke to protect himself. It could be said that Ksaver was Zeke's guide.
"Mr. Ksaver, am I really doing the right thing?" Zeke asked hoarsely.
Ksaver smiled and nodded.
"Of course, Zeke. You've done very well, and you're absolutely right. Believe in yourself. The mission of erasing the sins of the Eldians rests upon your shoulders. Strive to complete the euthanasia plan."
Zeke's lips trembled, but the figure of Mr. Ksaver suddenly vanished.
All around him, countless figures emerged from nowhere. Men and women alike—none of them familiar to Zeke. Their faces were filled with despair and resentment. Some even wore armbands marked with a multi-pointed star.
They were Eldians.
Endless Eldians surrounded Zeke. They cursed, roared, wept, and demanded answers.
"Why are you taking away our right to reproduce?"
"Why are you making us go extinct?"
"Why? What gives you the right to make us disappear?"
...
Zeke tried to explain, but more and more Eldians crowded in. Shoulder to shoulder, they pressed him in from all sides. The crushing force made it hard for him to breathe.
Suddenly, a vast expanse of blood-red appeared above him. Loud infant cries rang in his ears. Though he could not understand them, he somehow knew—they were unborn Eldian children questioning him.
Why take away their right to be born?
They were lives too.
Why?
"No! That's not it! You don't understand! I'm doing this for the future of the Eldians! I'm doing this so the sins will disappear! Why won't any of you understand me?! Why?!"
Zeke collapsed to his knees, covering his ears as he screamed.
A figure suddenly appeared before him.
Trembling, Zeke lifted his head and saw those emotionless eyes. Seeing him, Zeke felt as though he had found salvation. In a frenzy, he grabbed the man's shoulders, eyes bloodshot as he shouted:
"Eren! My brother! You understand his heart, don't you?! You understand me, right?! We're brothers! You must understand me, right?!"
But the Eren before him showed no emotional reaction at all. Tilting his head, he said:
"What are you talking about, brother? Why euthanasia? I still want to live. Why take away our right as Eldians to survive?"
Zeke's voice trembled.
"But our sins… the sins of the Eldians…"
Eren leaned close to Zeke's ear, whispering like a demon:
"Then let's just make the world never hate us again, brother. Together… let's trample the entire world flat."
Zeke froze.
"What did you say?!"
Eren burst into hysterical laughter. Then his body slowly fragmented into pieces and vanished before Zeke's eyes.
Zeke reached out to grab him, but grasped nothing.
"How pathetic, Zeke. The Eldian euthanasia plan has always been nothing more than your own joke, hasn't it? Why would you believe we'd cooperate with you to complete such a ridiculous plan? It's as laughable as a child's fantasy. You're so naive."
The mocking voice came from in front of him.
Black hair, black eyes, a face full of ridicule—Zeke saw the face of Yago Norman. The words from Yago's mouth filled him with rage.
"Bastard! Who are you calling naive?!"
With a furious roar, Zeke threw a punch straight at Yago's face.
...
"Ah!! Warrior Captain! What are you doing?!"
A pained howl jolted Zeke awake.
He opened his eyes to the sight of an army-green tent. Sitting up groggily, he finally saw Porco sprawled on the ground, clutching his nose.
Blood seeped through the gaps between Porco's fingers. Zeke raised his fist and stared at the blood on it.
Had he done that?
Porco stood up, still holding his nose, silently cursing his luck. He had only come to wake the Warrior Captain, yet Zeke apparently had quite the temper upon waking. He had merely given him a light shove—and suffered this disaster for no reason. What rotten luck.
Porco grumbled, told Zeke to get up and head to the command room for assembly, then left.
Zeke stared blankly at his own fist.
"Was all that just now a dream? But… it felt terrifyingly real."
He picked up the clothes beside his bed and slowly began dressing. Everything that had happened in the dream left his heart pounding. It also made him suddenly realize that the euthanasia plan might not proceed as smoothly as he had imagined. There were too many variables.
For example, Eren.
He had never truly spoken properly with his younger brother.
And the last figure in the dream—Yago Norman.
One thing Yago had said was right. Why should he believe that Yago Norman was sincerely cooperating with him to complete the Eldian euthanasia plan?
Yago did not know that, thousands of miles away, because of a single dream, Zeke's guard against him had risen to its absolute peak.