Armin joins the school in Episode 10, along with his twin brother Alexy. He is known for his passion for video games, hatred for the outdoors, and often makes various geek references. It's also revealed that he cosplays in Episode 20 when speaking to Lucy.
Armin has black hair and light blue eyes.
Overall, he appears to dress stylishly for he is normally seen wearing a purple scarf, a light brown undershirt, an egg-shell colored over shirt and a navy blue vest, jeans, and multiple bracelets on his left hand. However, it was mentioned that his brother Alexy is the one that picks out his clothes for him as he dislikes shopping, especially with Alexy.
In Episode 21, you get the opportunity to see him in different costumes.
In Alice in Wonderland, he wears a blue button up. Over that, he wears a purple tail coat with black trimming. The cuffs of his jacket are a green checkered pattern. Across his stomach, he has green checkered strips of fabric in a X shape. He has a green checkered tie. He wears a green checkered belt with a gold plait on it. On his hands are white gloves. His pants have black and white vertical stripes. He wears a black top hat with the top of it coming off. The hat has a green checkered sash and an ace of hearts followed by a second card sticking out of the sash. He is dressed as the Mad Hatter.
In Little Red Riding Hood, he wears a brown bear suit. The suit has a light brown stomach and the inside of the ears are light brown.
In Sleeping Beauty, as Maleficent, he wears a long cloak, The collar is spiked up with lime green lining. He wears a black helmet that resembles dragon horns with lime green tips. He holds a staff with a green orb on the top.
As the dragon, he is in the back. The dragon is black with silver lined wings. The rest of the dragon has green detailing, eyes, and gloves.
In Episode 25, like the other students, he wears a white lab coat for science class. He does not wear the goggles.
In Episode 32, he reveals he went shopping with Alexy, a "special treatment" get gets about 3 times a year, giving him his current outfit, a blue beanie, and a gamer shirt. If you're dating him, he'll mention that Alexy took him out to cheer him up after visiting Lysander the day before.
Armin is a gamer and loves to play video games. He has shown signs of his addiction towards video games several times, and usually carries around his PSP. Some games that he's talked about in particular are the Sims and Guitar Hero. He also enjoys Anime.
In Episode 14, when your Candy was looking for two more musicians to play in the band with Castiel and Lysander; Armin claimed knowing how to play the drums; but later he told the group that he was talking about playing drums on Guitar Hero. Castiel and Lysander seemed a bit angry on that but Iris found it funny and felt bad that Armin couldn't really play with them, since she would have liked to get to know him better during practices.
Unlike his brother, Alexy, Armin is quite interested in girls. In Episode 15, when your Candy asks him if he has seen a girl with long brown hair and ripped jeans (Deborah), he says that he would have liked to see that. In the same episode Armin offers your Candy some help in finding more information on Deborah (which was later revealed that he actually just wanted to get his video game back from the teacher's lounge). When your Candy corrects Armin every time he says Deborah's name wrong, he seems to enjoy it and says her name wrong on purpose. In Episode 20, Armin is also found interested in talking to Lucy; and when she asked him if he wanted to accompany your Candy and her to the courtyard, he happily accepts.
Armin is shameless and seems to have quite a perverted mind. In Episode 17, when Rosalya talked about your Candy's underwear in front of boys; unlike the other boys, Armin didn't blush or keep quiet, he easily commented about your Candy's underwear without getting embarrassed. He reveals in Episode 12 that his brother, Alexy, shops for his clothing. In Episode 18, when your Candy goes to get rabbits from the science lab with Nathaniel and Armin, a rabbit fell asleep on Candy's arms, close to her chest, to which Armin comments: calling the rabbit lucky to be sleeping on Candy's chest.
Armin is also known for being super lazy. Most of the teachers have already called him “Lazy", "Idle", "Dispersed". In Episode 20, when your Candy asks him if he has learned the text that Mr.Boris gave them, he said that he preferred doing that on the day of Auditions, to which your Candy calls him "Carefree" and an “I-don’t-care-ist” kind of person. Armin doesn't prefer flashy and bright clothes; instead he likes black and thinks that girls in black clothes look good. He hates being in the gardening club, because he thinks it's too bright.
Your Candy and Armin will have a good relationship if your Candy is a bit knowledgeable about video games or even not. In Episode 15, when your Candy comes out of Classroom B after hearing Mr. Faraize's announcements, she accidentally slips and Armin helps her to get up. He also jokes openly to your Candy and has offered her to play with his video game many times. He seems to get jealous when Candy bought a gift for Alexy, but not for him.
Armin first joked about Kentin having leveled up, just like in Pokemon. Armin and Alexy also joked about Kentin wearing things like, military pants, that are out of fashion; but when Kentin was sad on hearing rude comments from Lucy, Armin helped him to feel better by taking him to his brother. Although Kentin sometimes claims to find both twins annoying, he never makes a move to get away from them.
Armin's parent's; Victoria and Arnold, are not the slightest bit strict and don't stop him from doing anything he likes, like staying up the whole night to play video games. Armin describes them as cool parents, and both the twins are rather fond of them. Arnold is calm and laid back just like Armin; while Victoria is funny and likes to joke around like Alexy. Alexy and Victoria often join forces against Armin and Arnold, who don't stand a chance against them. It is revealed that the twins are adopted, however this topic isn't at all sensitive to either of them. Armin even jokes about it in Episode 27.
Being twins, Alexy and Armin are very close. They share a sense of humor and trust each other completely. Their quarrels usually start due to their different tastes, such as a quarrel they had about having a play about Metal Gear, although it doesn't happen too often and is usually not serious. They tell each other everything and are often seen together, and are also able to understand each other just by exchanging looks. Armin sometimes nicknames his brother "Alex".
- Armin and Dake are characters who originally weren't planned for the game. They were added during the creation of the respective episodes they appear in.
- Armin is usually seen playing on a PSP, but in the purchasable figurine design of him, he is holding both his PSP and a blue Nintendo DS. He has a Red 3DS in the new Chibi Artwork.
- During the play Sleeping Beauty, Armin speaks the famous phrase from Gandalf, a character from several books written by JRR Tolkien. Although not in the text, he confronts Nathaniel saying "You will not get through!", a translation of the original version of "You shall not pass!".
- Armin is the only character based on a real person, ChiNoMiko's boyfriend. While he was for the initial creation, they no longer share anything in common.
- Armin is the older twin. That said, as revealed by Alexy in his second Artbook interview, the twins themselves don't know as they were adopted as babies and thus, their adoptive parents don't know.
- Alexy and Armin were originally Libras. This change was adapted because of a typo in the first artbook.