The creator of AoT has admitted that Levi does gave mental issues, most likely OCD or OCPD.
Losing his mother, the only family he has ever known in a cruel world, would be traumatic enough, but Levi's inability to leave her room, whether from a desire to join her in death or a dependency that left him without options, punctuates the sadness of his early life.
Reiner has severe depression and dissociative Identity disorder and PTSD. Bert: Severe Depression. Erwin and Annie: Depression. Levi: PTSD and Depression as well as OCD.
Armin also apparently suffers from schizophrenia, as he has an imaginary cat he calls "Mr. Whiskers".
Schizoid Personality Disorder
Eren can talk to a therapist to recognize his ways of thinking in a more positive light.
Levi has PTSD. Severe PTSD. Post-traumatic stress disorder (PTSD) is a type of anxiety disorder. It can occur after you have gone through extreme emotional trauma that involved the threat of injury or death.
Eren is shown to believe in freedom and have some sort of obsession with it. One of his biggest dreams is to be free and to free humanity.
7 Levi Ackerman Has Contamination OCD
Levi Ackerman from Attack On Titan seems to exhibit behaviors that align with contamination OCD. Levi despises unclean things, especially a filthy environment. He even takes the time to clean his weapons while he's still on the field.
Yeah, Reiner seems to suffer from a case of Dissociative Identity Disorder (DID) which he creates an alternate personality, maybe to save himself.
Although he harbors convictions, he is also cowardly. Reiner suffers from severe psychological trauma in Paradis, which coupled with his mother's insistence and his own disillusionment with Marley, makes him extremely depressed and suicidal.
Hajime Izuyama, the author of the popular manga series attack on Titan, gives us a glimpse into levy's world. in which he only sleeps for 2 to 3 hours per day. and suffers from insomnia. His dreams are filled with terrifying screams.
5 Levi's Relationship With Sleep Isn't Ideal
And Levi does, in fact, have sleeping problems. Specifically, he struggles with insomnia, averaging only a few hours of sleep each night. Because of his insomnia, Levi also views sleeping as a "nonevent" — so much so that he doesn't bother with a bed or pajamas.
Levi is definitely asexual.
We have seen Levi cry only once so far in the manga. It was during his backstory, when he was a young boy and Kenny took him under his wing he tells Levi to fix his hair.
Levi was severely injured after Zeke blew himself up with a Thunder Spear. As the blast blew him away, he was left in a horrific state and lost many of his fingers. More so, during the final battle to stop the Rumbling, Levi loses the use of his legs whilst still healing from his prior injuries.
In Levi's eyes there is a great sadness following Hange's sacrifice. Unlike the others, he does not watch Hange's death but quietly sits and says “See you” to Hange, and asks them to watch him and the others.
In Attack on Junior High Manga, Reiner has an enormous crush on Krista. In the manga, Reiner is always willing to help Krista whenever he can, and Ymir doesn't mind him as he helps Krista. However, in the anime, Ymir always pushes Reiner away every time he tries to assist/save Krista to save Krista herself.
Bertolt and Annie were both Warriors from Marley, and Bertolt developed romantic feelings for Annie. It is unknown whether Annie knows about this. The two, along with Marcel and Reiner, are sent to Paradis to retake the Founding Titan.
History. Reiner comes from the Liberio internment zone in Marley, which he refers to as his hometown. He was born to an Eldian mother, Karina Braun and a Marleyan father.
Levi was one of the few characters never to have been intimidated by any of these goliaths even early into his career under the watch of Erwin Smith. Instead, his only fear is of the potential loss of his comrades, especially in his first missions.
Its confirmed by Isayama that Levi had no love interest in the manga/anime. He never loved Petra nor was he gonna get engaged to her.
Wren is also having difficulty controlling her alcohol consumption and finally, Levi is dyslexic – he has a severe learning disability.
In the Attack on Titan Junior High series, it's heavily hinted that Annie has a crush on Eren, who's very oblivious towards it.
Effectively, when Season-3-Eren kissed Historia's hand, he saw his entire future. Whatever Eren Yaeger's ultimate goal is as of Season 4, Episode 20, it's so terrible that his own father begged Zeke to stop Eren, even though Grisha had been cooperating with Future Eren's instructions up to that point.
“But when did try to do that?” Here's what I think: Eren fixed/built/changed the past in order to have the future that he wanted, which is to destroy the world, and he did all of that WHILE having sex with Historia(Because she has royal blood), which leads to him to being the father of her child.