I am referring to when he has trouble turning into full-sized Titan after he underwent intelligence and endurance testing. It happened in chapter 53 of the series, during the Uprising Arc.

This is a quote from the Attack on Titan Wiki:

During an experiment to test Eren's hardening abilities, a severed Titan form of Eren falls to the ground. Hange is unable to get a response from him and because Levi notices that this Titan is underdeveloped, Mikasa and Hange remove Eren's body from the Titan. [...]. A day later, Eren finally wakes up. He doesn't seem to remember anything from the experiment and is upset to find out that there were no signs of the hardening ability. Hange explains that since Eren transformed without being able to employ the hardening ability, they decided to run intelligence and endurance tests. [...]. However, after one hour of testing, Eren suddenly, after writing something about his father, became unable to perform the tasks and eventually left his Titan body. After thirty minutes of rest, he transformed again. However, this time his Titan form was only 13 m tall, contrary to the usual 15 m, and couldn't perform any of the intelligence tests. For the third time, the Titan was only 10 m tall and was incomplete, with his human body being attached to it more firmly than before. Eren takes this news as a proof that the operation to retake Wall Maria cannot be performed at the moment.

Why did this happen and how was it resolved?


7 Answers 7


I'm pretty sure this is due to the fact that turning into a titan requires energy. Serially turning into one like that was wearing him down, such that he couldn't turn into the normal full-sized titan of normal titan intelligence. If he burned enough energy as a titan or through regeneration, he would not be able to turn into a titan at all for a while, as established much later in the manga.

  • This should be the selected answer
    – AdiG15
    Commented Jan 30, 2021 at 14:05

Nobody knows why this is happening. Even Eren can't remember what actually happened and it has not been resolved till now(59). Currently they are following Erwin's plan. The question may be answered in the future.


The reason why Eren can't sometimes turn into a titan because he doesn't have a objective to focus on, unlike his first transformation which he focus of not dying and the vision of his mother, sometimes his anger trigger his tranformation. For example, Annie's tranformation was easlier for her because she had to be cold blooded when getting Eren. Before the last espiode Armin told Eren to leave his humanity and became a monster to able to fight Annie. I haven't read the manga but I do my research on Attack on Titan and I will read the manga.


Eren cannot transform, for purpose. Because it's is possibility that's transform into titan will need sunlight and energy. I'm certain sure Eren need sun light/energy and bite his finger at same time. In episode 23-24, Annie avoided to go dark underground. If she went into and bite finger, she wouldn't be able to transform. That's why Annie and others titan shifter alway on outside in order to transform.


The reason is the plot :D He had to be captured by Kenny's goons so the story could happen :D

Ok, but with all seriousness, Eren needs to be strong, both mentally and physically. After dozens of test he was probably. He didnt knew his limits back then and before test he managed to fully transform only 3 times - all of them very randomly.

Also i think it depends on how strong Titan Power is.

SPOILER: Carting Titan is probably the weakest, but can stay in titan form for the longest. Colossal Titan is huge, so he is very concious about to when to transform into one - Ww can see Nertholdt transformin io Collosal's upper body in season 3, but then day later h is carried by Reiner. He never rly fights back when he and Reiner are attacked by mindless titans even if they both almost get eaten, so he probably needs a lot of energy to transform. Eren has 2 titan powers. His transformation is probably more demending than armored or female titans.


The reason why he can't turn into a Titan at will is because he can only do so if there is a set goal in mind. Which is also why he could not turn in to a Titan when he was in the well, but later on when he was sitting at the table with the rest of his squad and he dropped his spoon and then proceeded to pick it up, he grew a Titan arm.

  • 1
    Please read the question again, you are thinking about the wrong event.
    – nhahtdh
    Commented May 7, 2015 at 5:22

I think eren didn't have enough energy and sunlight so he was not able to transform into full titan. So thats why annie and zeke if always outside to transform.

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