The Myers-Briggs Type Indicator questionnaire is a psychological and personality profiling tool that many people use to gain insight into their preferences, world views, relationships, and career choices. Through the test, people are classified as exhibiting primarily one trait in a series of four pairs. Those traits are Introversion/Extraversion, Sensing/Intuition, Thinking/Feeling, and Judging/Perception.

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People who exhibit Introversion, Sensing, Feeling, and Judging (or ISFJs) are labeled “Defenders.” Defenders are reliable, put other people ahead of themselves, feel for the plight of others, and seek to make a positive change in the world. This describes a lot of heroes. But some heroes embody these traits more than others. Here are 10 Marvel superheroes that would be classified ISFJs on the Meyer-Briggs Test.

10 Captain America

There is no doubt that Captain America is the epitome of a guardian. Dedicated, unyielding in his belief in standing for what’s right, Cap is always working hard to be a role model of the best ideals.

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He’s aware of the attention that wearing a flag as a costume brings him, but he doesn’t seek it out. In fact, he only seeks the spotlight when it serves his purpose as a guardian. As his membership in the Avengers proves, Captain America is the “universal helper” that experts say Guardians often are.

9 Guardian

As the leader of Alpha Flight, James MacDonald Hudson uses his exoskeleton and the name Guardian (after being Weapon Alpha and Vindicator for a time). He’s an unsure leader, at first, more interested in service than the spotlight. This service brings him into conflict with the X-Men when he’s tasked with bringing Wolverine back to Canada.

This eventually works itself out, as hero-on-hero disputes often do in comic books. Mac would go on to lead Alpha Flight for several adventures, sacrificing his own life — multiple times because “comic books” — in the process. Guardian, indeed.

8 Groot

When Groot made his initial appearance in Tales to Astonish #13, he wasn’t the humble, heroic treeman that we’ve all grown to love, rather, he was a monster, hellbent on Earth’s destruction. Thankfully, this all changed in 2006, and the historic monster-Groot has been ret-conned to be a different member of the same species as hero-Groot.

Now, this new Groot is defined by his fearless devotion to his friends and his ability to re-spawn from just a sprig of himself. Everyone should be looking for a chance to say, “We. Are. Groot.”

7 Thing

Deeply introspective after the accident that gave him his powers, Ben Grimm decides to help others instead of wallowing in self-pity. Several times in the character’s history, The Thing forgoes a chance to revert to human form in favor of staying his rocky, powerful self, which allows him to continue fighting for what’s right.

Fiercely loyal to his extended Fantastic Four family, and the under-privileged and the different, The Thing is a guardian for anyone who needs one. There’s nothing more human than that.

6 Luke Cage

Luke Cage in the Marvel Comic Universe

Power Man’s history is a trip through the popular culture zeitgeist, shaping and being shaped by the social concerns of the time. Cage’s dedication to helping people who need help has never wavered, though, and especially in modern times, the character has shown the softer side attributed to ISFJs.

Now thoroughly dedicated to providing a safer world for his daughter, Danielle, Luke Cage continues to be a Guardian to everyone who needs one.

5 Daredevil

Few heroes show such dedication as Matt Murdock, also known as Daredevil. As one of Marvel’s premiere “street-level” heroes, Daredevil’s stories often depict him going toe-to-toe with evil to protect the common man and woman.

Guardian-types are altruistic, like so many heroes, but also have the skills and work ethic to put that desire to be helpful into practice. Daredevil is tireless in his desire to protect the people of Hell’s Kitchen, whether his swinging from buildings or facing off against Wilson Fisk in the courtroom.

4 Warlock

Warlock was so dedicated to protecting his friend Cypher (Doug Ramsey of the New Mutants) that his smothering attention actually harmed Cypher’s self-esteem. His Guardian-tendencies are a result of a mutation. As a member of the alien Technarchy race, Warlock should be always looking to drain the lifeforce of other creatures. But he feels empathy for other sentient beings, which brings him into conflict with his own people.

Eventually, Warlock’s devotion to his friend results in some pretty odd stuff (grave-robbing among them). His heart’s always in the right place, though.

3 Quasar

Quietly one of Marvel’s most steadfast and most powerful heroes, Wendell Vaughn wields the Quantum Bands, which sort of let him become Green Lantern, but with less of a smug attitude. In fact, Quasar’s lack of killer instinct in favor of a more mellow attitude is what lets him be such an effective user of the Bands.

Quasar is a cosmic hero, and most of his adventures send him far away from Earth, but he’s always thinking of home, and the loved ones he works to keep safe. Eventually, Vaughn learns that the Bands are meant for a hero with the title “Protector of the Universe.” He accepts the role, and all the responsibility it entails. Not bad for a humble guy from Wisconsin.

2 Vision

Few characters have been subjected to as much heartache as the Vision. His origins are complicated, his family life is a mess, and death is always right around the corner.

Still, he’s always tried to do what’s best for everyone he loves. He even learned to love. His most recent series is a primer in how a Defender must make hard choices as everything around him unravels.

1 Flatman

Flatman admitting he failed Good Boy

As a member of the Great Lakes Avengers, Flatman uses his powers to fight evil wherever he finds it. Although the GLA is often played for laughs, its members are legitimately sincere in their desire to do some good. This unique blend of humor and earnestness matches the characteristics of a Guardian perfectly.

Flatman’s not the smartest, and he’s not the strongest, but he makes do with what’s available to him. Along the way, he’s proven himself a hero of tremendous heart. A 2-D heart.

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