For whatever reason, Isayama, as talented as a writer he is, made his ending incomprehensible and meaningless because he couldn't decide which ending to go with. He admitted that he changed the ending several times as AOT gained popularity, but he failed to come up with a satisfying conclusion that fitted the story and themes of AOT. His ending product was just a baffling mess that goes against everything he built up before.

In a nutshell, the complete ending adds nothing of value.

We learn nothing of value about the other characters. We are not shown the development between Paradis and Marley in terms of peace talk or show us closure of certain characters; such as Reiner or showing us how the peace ambassadors of the alliance are representing Paradis or we do not learn about their accomplishments and progression in life, we just get a multitude of plot holes on top of other plot holes.

Let's just jump into it, because it is going to be long because this series was once my favorite series.

So in the first scene, it is revealed that Ymir is the cause of Mikasa's headaches. That's a massive plot hole because it turned out that Ymir wanted Mikasa the whole time.

So since it turns out that Ymir's been poking around in Mikasa's head, that means that Ymir was already in contact with Mikasa to begin with. So why didn't Ymir ever just contact Mikasa directly? Mikasa was pulled into the Paths once Eren started the Rumbling, so she can be summoned there at any time so why didn't Ymir speak to Mikasa there? Was it really necessary to commit a genocide JUST so Mikasa can supposedly get over Eren and talk to Ymir?

And since we're on the whole Ymir and Mikasa aspect, why did Ymir want Mikasa specifically? Because think about it, out of the billions of women in the world who undoubtedly faced an abusive relationship, it was Mikasa that Ymir needed the most. Why? Why does Ymir need an inexperienced child to tell her about love? Mikasa and Ymir are not similar. Not even close. Ymir was a slave who was forced to become the King's concubine. She had Stockholm syndrome. Mikasa is Eren's adoptive sister who CHOSE to devote her life to him. Mikasa had the freedom to make her own decisions, Ymir didn't. Mikasa is nothing more than a naive, immature child with a obsessive crush on a boy that treated her like garbage, awhile Ymir is just a slave.

And the main thing I hated about the ending concerning Ymir, is that she is never held accountable for terrorizing humanity for centuries. Yes, Ymir is a victim, but she victimized countless generations, she is no better than the king himself. And because of the retcon, Ymir looks even worse because she lost the excuse that she had no free will. She clearly did considering that she chose Eren over Zeke. She was not trapped in the Paths. She chose to create Titans on the behalf of the King, and let them terrorize Paradis. And then to rub salt on the wound, she goes on to commit to a global genocide, killing MORE countless people for no reason.

She shows no remorse for her actions and never takes no responsibility. The whole scene was just so hollow because it's a scene between two flat characters that were shoved in together for this contrived storyline.

In fact, I am positive the manga was retconned because every chapter before 139 makes absolutely no sense. Especially CHAPTER 120-123 where the chapter heavily implied that Ymir contacted Eren because he understood her since they both held the desire for freedom and Eren didn't treat her like property like Zeke did.

And most importantly there was no mention of Mikasa or even love whatsoever. Although it was never said, the story at this point seemed to build up the narrative that Ymir simply wanted a new life. The story prior to 139 had it all set up with Historia's pregnancy, the mystery with the paternity, and the overall timing, it made sense to believe that Ymir simply wanted to be reborn and given a new chance at a new life.

But in the end; all that was just a red herring. The story changed drastically to Ymir is just lovesick and she needs an obsessive teenager with no similar parallels to her to tell that her love life is a nightmare and she herself is a victim. (Because apparently the King burning down her village, tearing out her tongue, forcing her to bear his children, and then forcing their three children to cannibalize her corpse was not obvious enough.) All of the retconning puts so many plot holes on top of other plot holes. Why did Ymir not listen to Zeke if she loves the King? Why did she listen to Eren? Why didn't Ymir request Mikasa immediately? Why did she cry when Eren told her she was not a god? Why did Ymir send a message to Eren 2000 years ago if she just wanted Mikasa?

Nothing makes sense.

The next set of plot holes is the lack of the realism. For some reason there is a time of peace after a genocide that killed 80% of the world. Paradis is destroyed after a few timeskips. Assumingly decades after the original story because they have fighter jets now. And now I'm going to get into why this part of the story is bullshit.

Not the fact that Paradis got destroyed in the war. That's honestly the only realistic aspect of this chapter. But it's when Paradis got destroyed. AOT beforehand had a good sense of realism to it. Hence why the hopeful theme of 139 doesn't work. Genocide never goes into peace. Never. There would be no period of peace and harmony. It would not take a couple of decades for Paradis to be leveled. No. Paradis would be bombed within at least a two-four years at most. Not decades and decades later. No. As soon as Marley and the other nations manage to rebuild their weaponry, Paradis would be immediately wrecked. There would be no long waiting period. Mikasa would not have the time to make a family and live and die in peace. No. It would be all out war immediately.

Heck, realistically the Marleyans would have shot all of the Eldians immediately and that would be it. There would be no questions like "Can you still turn into Titans?" Especially after you all witnessed them turn into Titans two seconds ago.

There would not be YEARS of peace and calmness of any kind.

Isayama should have not gone down the genocide route if he wasn't going to take it seriously. You can not pull a Lelouch with a genocide. NOW the story just clings to the part where Eren said he wanted his friends to live long lives. But in the same breath, he also said he wanted to protect Paradis, and bury the hatred of the world, but Eren failed on those accounts. He even failed his original objective because the Titan powers still exist and Eren allowed Paradis to be just leveled. He allowed his friends to live long enough to see their children and grandchildren die later. To put it into perspective, Eren let his friends live a long life. But none of his friend's descendants and families. None of the innocent people of Paradis or Paradis itself. Eren let them all die. Eren could have very easily killed everyone when he was doing the Rumbling. There were so many incidents where the alliance could be murdered. They could have easily been killed by the thousands of Titans coming out of his spine. They could have died when the version of the Beast Titan threw rocks at the plane.

Even before all of that, he caused Sasha to get killed, he got Hange killed. Floch got killed. Connie was nearly shot dead by a Yeagerist and nearly killed again on Eren's spine. Armin got swallowed by a Titan. Levi was on the verge of death himself.

And even then Eren still took a huge gamble by letting them survive all of this anyway.

I know that the entire cast are hardened warriors. But still. Just imagine the emotional and mental toll that the alliance experienced. Surely witnessing millions of women, children, and men being slaughtered by Titans can truly break a mind. They would not come out of this unscatched. There is so much a person's mind can take before it breaks. Basically Eren cursed them with long lives full of PTSD, night-terrors, depression, and survivor guilt. It would have been more realistic if any of the alliance just suffered a mental breakdown and offed themselves a few months later.

Heck, the suicide rate in general would skyrocket straight after this. No one would bounce back from this. No.

Also, I noticed that Isayama conveniently refused to mention the alliance's situation with the Yeagerists. Because in the end, the Yeagerists are in full force at this point, and the alliance is still heading back to Paradis, but nothing happens to them because Historia is still Queen for some reason.

I say some reason because the Yeagerists were established to be a fascist, extremist group who literally took out most of the government officials. But yet they're fine with having a Monarchy?

Anyway, so there is a defense for this conclusion, people have argued that it was realistic and meaningful as the real world is at war and never in peace. But that argument doesn't work when you introduce the Rumbling. The Rumbling by all means was established as the final solution. Deleting the rest of the world to protect one nation. There would be no war from the outside world. (You could argue that there would be unrest within Paradis itself because of differing opinions on the Rumbling. But still.) From chapter 120-134; Eren's motivation for committing the Rumbling was fully established.

But in the end, it turns out Eren is not only incompetent idiot, but a spineless coward who murdered millions on a blind whim and doesn't even have the balls to face the consequences of his actions. When he was asked about his motivation by Armin, he literally said I don't know why I did what I did.

It's not vague or mysterious in a way to intrigue the reader, it's just a lazy, frustrating cop out. Eren just committed a full blown genocide, slaughtering countless men, women, and children alike, and his answer to why he did it was I do not know. He apparently forgot EVERYTHING he said in the previous chapters where he bluntly announced his own motivations. To Floch and Historia and the whole world respectively. But now he's a complete clown because Isayama just gave up on giving a logical explanation. Eren is worse than his young self, because despite how annoying his younger self was, he at least had conviction on why he was doing what he was doing. Young Eren had his reasons and motivations established from the beginning and throughout the course of the story, Eren supposedly grew and his motivations evolved over time. He seemingly developed into a well-rounded character that was mature, rational, and strategic. He was determined in ensuring the freedom and safety of his home, and he wanted to protect what mattered most to him no matter the cost. But in the end, all of that development from the previous chapters are just erased, it was made meaningless because in the end, Eren is just a worthless, incompetent mass murderer that just committed a genocide on a blind whim.

And to make matters worse, Isayama shoved in this needless soap opera at the end about Eren loving Mikasa. Instead of having the romance subplots in the background where they belong, Isayama shoved the romance on the center stage where it was not warranted.

There was never any chemistry between Eren and Mikasa.. it was a one-sided crush on Mikasa's part accompanied by her extreme codependency and unhealthy obsession.

Isayama's writing always seemed to indicate that they were growing apart, never together.

Like since when? Seriously? Every single time the poor girl has tried to show him any affection or care, Eren would push her away. He mistreated her, rejected her, and was just horrible to her. He downright resented her in the beginning. And what's worse is that Mikasa is such a wet blanket it is hard to watch. She is too submissive, and has no basic respect for herself.

Realistically Mikasa would never 'move' on, and with her codependence, she would never be able to have a stable relationship. Quite frankly I fully expected Mikasa to kill herself at the end because that's how demented Mikasa was. I do not believe for a second that Mikasa can go from crying her eyes out at Eren's grave like a widow, declaring that she wants him to be with her to falling in love with Jean or some random stranger, marrying him and moving on. No. That's not the behavior of someone moving on and becoming independent. That's someone who is still refusing to accept reality and just married someone else out of convenience.

All in all, 139 Volume 34 is terrible and the animals ending is equally terrible. It is senseless, it is contrived, it is poorly written, it is bad to the point of being impressive. It is a blatant cash grab. Isayama dropped the ball so hard on this that I can't even believe that he regrets how he executed this. I can't. Because on paper, this story is absolute trash. Isayama outlined this, made a rough draft, proofread it, and officially wrote it down. Anyone who has taken a professional creative writing class or just enjoys literature in general would never submit this.

(Now given my track record of writer blocks and inconsistencies and indecision, I know I may not have enough merit, but Isayama is truly talented, so it is baffling to see him drop the ball so hard.)

This is just my theory but I feel like the ending was changed at the last minute. Why? I have no idea. It could be for profit, maybe writer's block, maybe Isayama fell out of love with his creations, or maybe it was rushed. Who knows?

It felt so rushed and unprepared. It was so needless. The extra details in the story are unnecessary and to top it all off, the end is a lame sequel tease.

In my opinion, It's fine to enjoy the journey, heck, Isayama inspired me to write and so on? But I personally want to make sure my enjoyment was well-spent and AOT was just a sad disappointment. So I just let go of the series after the manga.