I find personality tests like Myers Briggs and the Enneagram fascinating, and wanted to explore what I think are the most likely Enneagram types for several SnK characters. Feel free to let me know what types you think the characters best fit with! 

(If you’d like a brief explanation as to how the Enneagram works, you can read one here!) 

Type One: The Reformer
Erwin Smith

Basic Fear: Of being corrupt/evil, defective
Basic desire: To be good, to have integrity, to be balanced

Type Ones are described as having “’sense of mission’ that leads them to want to improve the world in various ways, using whatever degree of influence they have. They strive to overcome adversity—particularly moral adversity—so that the human spirit can shine through and make a difference. They strive after “higher values,” even at the cost of great personal sacrifice.“ Erwin seems to fit this pretty well: he’s always looking to improve humanity’s situation, be it by finding out more about how to defeat the Titans, or in plotting to put Historia Reiss on the throne. He’s always putting the ultimate goal of saving humanity before individual goals/dreams/lives, including, the woman he loved (Marie) and, in the end, his own dream to see the basement, and his own life. 

Enneagram personality types also come with “wings”–an adjacent personality type also reflected in one’s personality. I’d say Erwin is more of a 1w2 (aka “the Advocate”) than a 1w9.

Type Two: The Helper
Christa Lenz/Historia Reiss

Basic Fear: Of being unwanted, unworthy of being loved
Basic Desire: To feel loved

Historia was one of the most obvious characters to type. The Enneagram Institute describes Twos as ”fear[ing] that they are without value in themselves, and so they must be or do something extraordinary in order to win love and acceptance from others.“ Historia literally believes that, as an illegitimate child, she should not exist. During her military training, she almost dies helping Daz during a training mission, and frequently engages in acts of kindness, to the point where everyone in her division openly adores her. But Ymir frequently calls her out on her desire to have everyone see her as good, as a martyr even, and on her fear of being a burden–like many Twos, she has difficulty acknowledging her own need–and this is ultimately good for Historia, as Ymir succeeds in helping her become a healthier Two via acknowledging her own worth. 

Historia strikes me as a 2w1 (aka “the Servant.”) She wants to be morally “good”–a characteristic of type One.

Type Three: The Achiever
Jean Kirchstein
Reiner Braun

Basic fear: Of being worthless
Basic desire: To feel valuable and worthwhile

Threes are described as ”self-assured, attractive, and charming. Ambitious, competent, and energetic, they can also be status-conscious and highly driven for advancement. They are diplomatic and poised, but can also be overly concerned with their image and what others think of them. They typically have problems with workaholism and competitiveness.“ Jean is unquestionably ambitious, as in the start of the series he’s driven to graduate in the top ten and get into the military police, and he’s definitely competitive with Eren. However, Jean is also charming, and well-liked, as is Reiner–Shadis himself observes that everyone likes Reiner. 

When a Three grows, they ”become more cooperative and committed to others, like healthy sixes.“ This is exactly what happens with Jean–he becomes more committed to his friends, particularly Marco. Marco’s death devastates him and becomes a catalyst for Jean changing his priorities and joining the Survey Corps. 

Jean I believe is a 3w4–aka, “the Professional.” He’s quite focused on his own individual reputation.

Reiner, in contrast, is a far unhealthier Three. Threes are also noted to run the risk of ”becom[ing] so alienated from themselves that they no longer know what they truly want, or what their real feelings or interests are. In this state, they are easy prey to self–deception, deceit, and falseness of all kinds… Step by step, their own inner core, their “heart’s desire,” is left behind until they no longer recognize it.“ This seems a pretty accurate description of Reiner (who also appears to suffer from dissociation of some sort). Reiner is truly unable to know what he wants, to the point where his personality is literally split–one part wanting to fulfill whatever the Warriors’ mission is, and the other one wanting to be a big brother to his comrades. 

Reiner is, I believe, a 3w2, “the Charmer.” He likes helping his comrades… which is certainly ironic, in a tragic sense.

Type Four: The Individualist
Annie Leonhart

Basic Fear: That they have no identity or personal significance
Basic Desire: To find themselves and their significance (to create an identity)

Annie was really hard to type, but I’m going to say I think she’s a 4. Annie makes it very difficult for people to get to know her, and Shadis observes that she’s a "lone wolf.” Despite sharing a mission with her, Reiner and Bertolt don’t seem particularly close to her, with their comrades even observing that they never saw Annie talking to Reiner or Bertolt. Fours are noted to “withdraw to protect their self-image” which seems pretty fitting for Annie. In addition, despite being a lone wolf, Annie clearly cares very much about what people think of her–a trait shared by many Fours. She knows there’s a significant chance Armin’s recognized her as the female Titan, and she still agrees to help him, simply because she doesn’t want to be a “bad person” to him. 

Annie is likely a 4w5 (”The Bohemian”). 

Type Five: The Investigator
Armin Arlert 
Hange Zoe

Basic fear: Of being useless, helpless, or incapable
Basic desire: To be capable and competent

Armin was another obvious one, as he literally says that he hates feeling useless. He evaluates his physical strength as lacking when compared to Mikasa’s and Eren’s, and while he’s grateful for their friendship, he wants to be useful in his own right as well. And as the series progresses, he discovers just how useful his mind can be–when it comes to convincing the Garrison to keep Eren alive, taking down the Female Titan and the Colossal Titan, etc., and grows into a healthier Five and a protagonist in his own right who, as Eren proclaims, might actually be the one to save humanity.

Armin seems to be a 5w6–known as “the Problem Solver,” which is kind of perfect. 

Hange also appears to be a Five, as Fives are described as “wanting to possess knowledge, to understand the environment, to have everything figured out as a way of defending the self from threats from the environment.” Hange’s obsession with wanting to learn about Titans, no matter the threat, makes her clearly a Five as well (and the drive for knowledge also applies to Armin). 

Hange, in contrast to Armin, seems to be a 5w4–aka, “the Iconoclast.”

Type Six: The Loyalist 
Bertolt Hoover
Mikasa Ackerman

Basic Fear: Of being without support and guidance
Basic Desire: To have security and support

Bertolt is another one I think has an obvious type. He’s a Six, devoted to Reiner, albeit not to his cause (as it seems as though he doesn’t really believe in it). He loves his friends in the 104th; however, his devotion to Reiner is his primary loyalty. All he really wanted was to return home–a place of security, really–and that, along with Reiner’s conflicted motivations, convinced Bertolt to turn on his friends (as, within the walls, they cannot provide him the safety he craves–in fact, given his true identity, they can’t provide him any security at all). He’s a 6w7, aka “the Buddy.”

Mikasa also seems like a Six, only her loyalty is with Eren and Armin–her family. Sixes “will typically fight for their beliefs more fiercely than they will fight for themselves, and they will defend their community or family more tenaciously than they will defend themselves,” and we see that the numerous times Mikasa saves Eren, and when she fought Levi for the titan serum to save Armin. Unlike Bertolt, she’s a 6w5–aka, “the Defender” (a name that fits her perfectly.) 

Type Seven: The Enthusiast 
Sasha Braus
Connie Springer

Basic fear: Of being deprived and in pain
Basic desire: To be satisfied and content—to have their needs fulfilled

Sasha’s love of food, and her determination to get it (even going so far as to steal from Shadis) make it clear she’s an enthusiastic person. She appears to be enthusiastic about everything she does, a trait that enables her to serve as primary comic relief throughout the series. I think she’s a 7w6, aptly known as “the Entertainer.

Connie also strikes me as a Seven, as he’s frequently involved with Sasha’s shenanigans. Sevens “are endowed with abundant vitality and a desire to fully participate in their lives each day” and Connie and Sasha both embody this. Connie, in contrast to Sasha though, seems to be a 7w8, aka “the Realist.” 

Type Eight: The Challenger
Eren Jaeger
Levi Ackerman
Ymir

Basic fear: Of being harmed or controlled by others
Basic desire: To protect themselves (to be in control of their own life and destiny)

Eren and Levi are both fiercely determined to be in control of their own lives and destiny. They both strive to maintain a sense of control over their situations (Levi far more successfully). Eights are also described as “us[ing] their abundant energy to effect changes in their environment—to’ leave their mark’ on it—but also to keep the environment, and especially other people, from hurting them and those they care about." 

As driven as both Eren and Levi are by their ultimate goal of eradicating the Titan, they both are very emotional people at heart, driven by those they love. Eren’s mother’s death was the catalyst for his determination to kill every last Titan, and his care for Annie, a person he considered a friend, left him unable to fight her. Levi’s care for Erwin comes through in his initial decision to inject Erwin with the serum, and his "soft spot” for Mikasa and Eren is apparent throughout the series. They don’t want their loved ones to suffer, and when Levi understands that prolonging Erwin’s life when he’s rejected the serum would be cruel, he loves his friend enough to let him die–in a sense, protecting him from more hurt. 

Eren appears to be an 8w7, aka “the Maverick,” whereas Levi’s more of an 8w9 (aka “the Bear.”) 

Ymir is also driven by her desire to protect Christa/Historia from harm, and she is willing to sacrifice her own wellbeing to accomplish that. Eights are noted to be “desperately afraid of being hurt emotionally and will use their physical strength to protect their feelings and keep others at a safe emotional distance. Beneath the tough façade is vulnerability, although it has been covered over by layer of emotional armor,” and this description applies to Ymir, Levi, and even to Eren as well. 

Ymir, like Eren, is more likely an 8w7, aka “the Maverick.” 

Type Nine: The Peacemaker 
Marco Bott

Basic fear: Of loss and separation
Basic desire: To have inner stability “peace of mind”

“Freckled Jesus” is most likely a 9. He displays great love for his friends, risking his life to save Jean during the Battle of Trost. He repeatedly is seen trying to quell tensions during the 104th division’s training, and is clearly sensitive to others’ feelings (such as when he tells people to stop asking Eren so many questions about the fall of Shiganshina). Unlike literally every other character, he’s never seen having a conflict with anyone. Even when the Titan Trio steal his gear and leave him to die, he begs them to talk it out, apparently sincerely–a seemingly naive move that fits with a Nine’s traits of “seeking to find simple and painless solutions to their problems." 

Marco seems to be a 9w1, aka “the Dreamer.”