Beware of spoilers!
- Demoted to Extra: Pretty much all of them in season 3, with the series shifting its focus to Mewni.
- Humans Are Average: Humanity in general is pretty bland compared to the rest of the multiverse: Mewmans have cheekmarks and access to magic, demons have fire powers, and we can't forget monsterkind either. At best, humans seem to be pretty open-minded, but that's it.
- Ridiculously Average Guy: Of the multiverse. Sure, humans have their quirks like everybody else, but they still pale in comparison to the rest of the multiverse.
- Unusually Uninteresting Sight: They're all seemingly unfazed by all the magic and monsters.
Rafael & Angie Diaz
Mrs. Diaz voiced by: Nia Vardalos
Marco's parents, who allow Star to live with them.
Tropes applying to both
- Adults Are Useless: Played with. They're generally absent from Marco's life and as such do very little to keep him safe from his and Star's dangerous adventures. They also remain ignorant of the very clear indications that Miss Heinous wants Marco dead and are mostly concerned with appeasing her when she shows up at their house so that they can prepare for dinner with their cool neighbors. However, they do take steps to help rescue Marco when they learn that he's been kidnapped in "Storm the Castle", and after learning about him starting a princess rebellion and making enemies who threaten his and Star's lives, they decide to be more actively involved. In Season 3, Angie starts to address Marco's issue with not having Star around, and shows real concern that the way Marco is conducting himself after returning from Mewni isn't healthy.
- Aesop Amnesia: They haven't absorbed the lesson that they need to keep an eye on Marco or at least spend more time with him.
- Amazingly Embarrassing Parents: Marco sometimes gets bothered by their extreme enthusiasm.
- Foil: To the Butterfly parents. While Star's parents are stricter and stiffer, Marco's parents are more laid back and open minded. As an added bonus, the Diazes wear warm color clothing, while the Butterflys wear cool color clothing.
- Happily Married: They are very affectionate with each other.
- High-School Sweethearts: In the "#Marco LIVE Animated Live Chat", Marco said in response to a fan. They loved each other for a long time.
- It Seemed Like a Good Idea at the Time: Allowing a foreign exchange student to live in your house when said exchange student is a teenage girl the same age as your son is probably going to have serious consequences, something that Rafael and Angie are shown to have realized in hindsight given the looks on their faces after Star makes her Anguished Declaration of Love to Marco.
- Like Parent Unlike Child: They are free spirits who embrace new experiences even if they are dangerous; in contrast, their son Marco is a very safe person, to the point he is almost doing it unconsciously.
- Nice Guy: The two are very cheerful, and welcome Star into their home with open arms.
- O.O.C. Is Serious Business: Rafael and Angie in "Heinous" acted very angry and strict to Star and Marco when pinning down Miss Heinous and Gemini who they believe have done nothing wrong. Star and Marco thought they broke into their home about to torture them. They didn't have time to deal with Marco and Miss Heinous so they want him to resolve his issue with Miss Heinous. Plus, they take Miss Heinous' advice to heart to keep an assertive eye on Star's and Marco's inter-dimensional adventures despite nothing has changed after that. Rafael has took some fatherly advice to Marco in "Starcrushed", and in "Return to Mewni", part of The Battle for Mewni TV special, Angie tries to cheer up Marco after Star's sudden departure.
- Out of Focus: For the first half of Season 2 and Season 3.
- The Pollyanna: Almost nothing gets these two down. Every new weird and dangerous thing Star introduces into their lives, they ecstatically embrace.
- Replacement Goldfish: Their second child is pretty explicitly an attempt to replace Marco after the latter has moved to Mewni; they even go so far as to name the new kid Marco, Jr.
- Sickeningly Sweethearts: They are usually seen as a lovey-dovey couple. In Star and Marco's Guide to Mastering Every Dimension, Star says that they can be usually be found cuddling on the couch. The episodes "Diaz Family Vacation" when it was their anniversary and in "Raid the Cave", in a surprise cameo, really show how affectionate they are after years of being happily married.
- Unnamed Parent: Only referred to as "Mom" and "Dad" by Marco and "Mr. and Mrs. Diaz" by Star. Mr. Diaz's name was revealed to be Rafael in "Storm the Castle" while Daron Nefcy confirmed on Twitter that Mrs. Diaz's name is Angie. She was first addressed by name onscreen by Jackie in "Bon Bon the Birthday Clown".
- Wacky Parent, Serious Child: Mr. and Mrs. Diaz are free spirits compared to their insecure, safety-minded son.
Tropes applying to Rafael
- Carpet of Virility: Mr. Diaz has a lot of body hair, which his wife likes to play with.
- Curtains Match The Windows: Like his son, Mr. Diaz has matching brown hair and eyes.
- Explain, Explain... Oh, Crap!: Rafael doesn't exactly understand why Marco is bummed out during the party but when he goes over the scenario, he realizes what happened and recommends that Marco and Star talk this out.Rafael: What could be weird? Two teenagers sharing a home. One boy, one girl. [beat] Oh. Oh, no.
- Hidden Depths:
- "Sleep Spells" shows that Mr. Diaz is a talented sculptor.
- "Storm the Castle" reveals the Mr. Diaz has a book of medical illustrations.
- Keet: Like his wife, he's a free spirit.
- Latin Lover: Being Mexican, Rafael is seen sometimes being romantic and falling in love with his wife, Angie. One reason why he still loves Angie is because of her beauty. Also, his chest hair really attracts her as she starts playing with it. In Star and Marcos Guide to Mastering Every Dimension, it is said that he and Angie can be usually found cuddling on the couch. Even after years of marriage, he still loves her passionately.
- Papa Wolf: Although it wasn't fully seen, Mr. Diaz (along with Mrs. Diaz) did put on armor and was ready to storm Ludo's castle to save Marco. This is shown in a lot more detail in "Hungry Larry", where Mr. Diaz at first appears to be terrified of Hungry Larry and struggling to comprehend what was happening but he's revealed to be in a Tranquil Fury that is able terrify Hungry Larry and forces him to leave in a hurry.
- Tranquil Fury: In "Hungry Larry", Mr. Diaz is able to defeat and terrify Hungry Larry when the latter had eaten his family and Hungry Larry even says that there's nothing scarier than a man who's lost everything.
Tropes applying to Angie
- Berserk Button: She's normally easy-going, but she becomes frighteningly angry when Marco doesn't give her a real hug (this might have also had something to do with her pregnancy affecting her mood).
- Fiery Redhead: Downplayed, as Angie is an energetic free-spirit, not Hot-Blooded.
- Genki Girl: Like her husband, she's a free spirit.
- History Repeats: She's deeply ashamed of her brief period of pretentiousness and conceit after she spent a summer in Europe during her youth and tries to warn Marco against being similarly snooty and hurting those close to him due to his recent Mewni adventures. However, at the end of Sophomore Slump, she decides to let Marco return to Mewni to have his "French Summer" even if it means it might result in him having to experience some harsh and disillusioning life lessons in the process as it was for her. Which, sure enough, happens in the subsequent episode.
- Mama Bear: Although it wasn't fully seen, Mrs. Diaz (along with Mr. Diaz) did put on armor and was ready to storm Ludo's castle to save Marco.
- Rapunzel Hair: Mrs. Diaz's hair reaches past her waist, and it's in a ponytail.
- Significant Green-Eyed Redhead: Mrs. Diaz has reddish-brown hair and pale green eyes.
Marco's newborn little sister.
- Badass Normal: Even though she can't cast magic like Meteora, she can still kick butt. Heck, Meteora says that she kicked her butt at one point.
- Beauty Mark: Like Marco, Mariposa has a beauty mark underneath her right eye.
- Big Ol' Eyebrows: Her teenage self shows she will grow up to have thick eyebrows like her brother.
- Bitch in Sheep's Clothing: She stops fighting Star and Marco and makes peace, but turns out to have been planning to use Star to get magic for herself. Ultimately Subverted, however, as she had an attack of concience and goes back on the deal she had made.
- Everyone Has Standards: As much as she wants to cast magic, she draws the line when she finds out that Wyscan's belly mouth has to eat Star in order for her to gain it.
- Freudian Excuse: She and Meteora are very paranoid, aggressive, and manipulative, but it's to be expected for children who grew up alone in a Death World like the Neverzone.
- Hair Decorations: Uses a tiny Stock Femur Bone as a hairclip.
- Happily Adopted: She and Meteora/Grobb were adopted by mountain women and grew up as sisters. They're very close, and their only request when leaving the Neverzone (besides a constant supply of food) is that they'll still get to grow up together.
- I Just Want to Be Special: She wants to cast magic like Meteora.
- Meaningful Name: "Mariposa" is Spanish for "butterfly", her parents most likely naming her after Star's family.
- Mixed Ancestry: Half-Caucasian and half-Mexican.
- Orphan's Plot Trinket: The penguin finger puppet Marco uses to tell Mariposa a bedtime story becomes her pendant after growing up in the Neverzone. Marco recreates the story with it to prove he's really her brother.
- Plot-Relevant Age-Up: Due to being lost in Hekapoo's dimension, she grows into a teenager. When she comes back to Earth, she turns back into a baby.
- Simple Staff: Her main weapon is a wooden staff.
- Smash Sisters: With Meteora/Grobb while they were in The Neverzone.
- Strong Family Resemblance: She shares Marco's Beauty Mark and hair. Judging by her aged-up self from the Neverzone, Mariposa will grow up to look just like a female version of Marco.
- What Could Have Been: In-Universe. Had Mariposa been born a boy, her parents would've named her "Marco Jr".
Echo Creek Academy
Jackie Lynn Thomas
A classmate of Marco's, and the object of his affections, although he initially can't work up the nerve to tell her yet. She's often seen with a skateboard.
She and Marco begin dating in the middle of Season 2, before breaking up early in Season 3.
- Adorkable: Her interactions with Marco when they're dating. Both "Starcrushed" and "Sophomore Slump" showed that she was able to drop her trademark stoic chillness and be a total goofball around him, with one of her favourite activities being her trying to get him to read her thoughts.
- Ambiguously Brown: Jackie-Lynn has tan skin that is similar to Marco's.
- Amicable Exes: With Marco. They start dating in "Bon Bon the Birthday Clown", but Jackie breaks up with him because she knew he wanted to be on Mewni. When they meet up again in "Britta's Tacos", Marco is afraid that he was horrible boyfriend to her, but she reassures him that he was a "standard boyfriend" and that they just didn't work. At the end of the episode, Jackie advises him to go after Star while Marco smiles at her and Chloe skating off together while holding hands.
- Bi the Way: She was in a relationship with Marco that lasted until the early Season 3, but in Season 4, she hangs with girl named Chloè that she met in France, and she is confirmed to be dating her.
- Brutal Honesty: In "Sleepover" after the Truth or Punishment box inflicts Body Horror on everyone at Star's sleepover, she, along with Janna, Pony Head, and (eventually) StarFan13, admit that Star's brownies were awful. She apparently learned her lesson, because in "Bon Bon the Birthday Clown", she does not hesitate at all to let Marco know that the chocolate milkshake snack he made for the two of them on their date tasted terrible.
- Childhood Friend Romance: She has known Marco since kindergarten, but she remained oblivious of his crush until he reveals it in "Sleepover". They start dating in "Bon Bon the Birthday Clown" but later break up.
- Chronically Crashed Car: Or in her case, her skateboard, which tends to keep getting broken.
- Crazy-Prepared: She's so enthusiastic about skateboarding that she somehow kept one (plus two helmets) hidden in her dress during her first date with Marco.
- Girls Are Really Scared of Horror Movies: In "Naysaya", she clings onto Marco's arm when they go see a horror movie together.
- Hartman Hips: Her legs are not the only noticeably curvy part of her body.
- Heroic BSoD: In "Starcrushed" when Star confesses her love to Marco, Jackie doesn't gasp or say anything, she just looks at the situation with a shocked, distraught expression and thousand yard stare, prompting Janna to give a worried glance to check if she is alright.
- Hidden Depths:
- According to "Bon Bon the Birthday Clown", she's apparently a bit of a history geek, though Marco moves on to his next scripted question before she can elaborate more on it.
- In "Starcrushed", her interactions with her new boyfriend Marco are noticeably goofier than her usual relaxed demeanor, showing a silly side that she previously kept more to herself.
- Innocently Insensitive: She wasn't aware of Star's crush on Marco while she was dating him and didn't realise how it was affecting her.
- I Want My Beloved to Be Happy: She gently breaks up with Marco when she realizes that he can't readjust to Earth and she doesn't want him to stay on Earth for her sake.
- Just the Way You Are: In "Naysaya", she agrees to go to the movies with Marco despite him having just spent hours telling her all of his most pathetic, vulnerable insecurities. In "Bon Bon the Birthday Clown", she recounts this and Marco's many other embarrassing, Adorkable moments when she's explaining that she admires how much he manages to keep going on despite them.
- Love Epiphany: As depicted in Star and Marco's Guide to Mastering Every Dimension, the moment when Jackie realized that she reciprocates Marco's crush on her was during Star's interview with her about it.
- Love Revelation Epiphany: After Marco is forced to admit his crush on her in "Sleepover", Jackie admits she doesn't know how she feels about her previous crush anymore. In "Naysaya", she invites him to go see a movie with her, and the episode "Bon Bon The Birthday Clown" has Jackie asking him out on a date.
- Mellow Fellow: "Easygoing" seems to be her default mood. In Star and Marco's Guide to Mastering Every Dimension, Star calls her "surprisingly alert for someone who looks like she just woke up."
- Motifs: Jackie has several connections with water such as her sea green eyes, blue hair stripe, sea shell necklace and sea foam green dress in "Bon Bon the Birthday Clown". According to concept art, she was planned to appear in "Hungry Larry" dressed as a mermaid. When she breaks up with Marco, it's on the piers at the seaside.
- Nice Girl: Jackie is likable, easy-going, patient and understanding. When Marco accidentally breaks her skateboard in "Cheer Up, Star", she is clearly upset, but awkwardly rides away on the front half of the board after telling Marco it's okay rather than get angry. She takes the whole "Naysaya" incident very well, fetching paper towels for Marco after he asks for them in the most awkward way, and listens to a long list of embarrassing confessions without judgement. Even her breakup speech to him in "Sophomore Slump" is surprisingly calm.
- Non-Standard Character Design: Not completely, but her eyes are drawn differently to everyone else's and have more definition in the irises.
- Noodle Incident: In "Just Friends", while returning the baby ducklings to their mother in the creek, Star and Jackie both mention and bond over having lived in that same creek at some point. While Star's story is a Continuity Nod to when she went on the lam as a fugitive in "Star vs. Echo Creek", the details of Jackie's story and why she was living in the creek are not explained.
- Oblivious to Love: She didn't know about Marco's obvious crush on her until he confesses it in "Sleepover". Star and Marco's Guide to Mastering Every Dimension has her suggest in an interview with Star that she was always aware of it on some level, but didn't really know for certain until "Sleepover".
- Put on a Bus: In Season 3 once she breaks up with Marco and is left behind when he goes to Mewni, not appearing until a bit in season 4.
- Relationship Upgrade: In "Bon Bon The Birthday Clown", she asks Marco out on a date, where they end up kissing.
- Romantic False Lead: She was Marco's target of affections throughout Seasons 1 and 2, with both getting together at the end of the latter while Star grew increasingly jealous. They break up shortly after the start of Season 3.
- Satellite Love Interest: In Season 1, Jackie doesn't have much of a role besides being the girl Marco's crushing on. This is even lampshaded by Marco in the episode "Sleepover", when he admits he never truly to got know Jackie beyond the image of her he built up, but he would like to try. Jackie is given more fleshed-out characterization from that point forward.
- She's Got Legs: Her legs are noticeably curvier in comparison to other female classmates. "Freeze Day" reveals that they weren't as muscular in the past. It might be a result of her skateboarding.
- Single Woman Seeks Good Man:
- Skunk Stripe: A sea-foam green one, since it's her favorite color.
- Spell My Name with an "S":
- In "Freeze Day", a glimpse of Marco's childhood shows a gold star chart with Jackie's name spelled as "Jakie", though this could simply be attributed to a toddler's misspelling.
- A more complicated example would be the placement of the hyphen in her full name. In "Naysaya", Marco mentions that he filled a notebook with his first name and her last name because he couldn't decide between "Marco Diaz Lynn-Thomas" or "Marco Lynn-Thomas Diaz", implying that her last name is "Lynn-Thomas". However, the Star and Marco's Guide to Mastering Every Dimension book gives her full name as "Jackie-Lynn Thomas" and calls her "Jackie-Lynn" multiple times, implying that this is her first name. Considering that it's never mentioned when Marco filled that notebook, and the fact that even up to the present day he assumed that her drawing of a green watermelon was of the moon, it could be possible that her full name is properly spelled "Jackie-Lynn Thomas" and Marco simply didn't know at the time that the Lynn was not part of her last name.
- Symbol Motif Clothing: She always wears a seashell necklace and has shown multiple times to have connotations with water, such as her dress in "Bon Bon The Birthday Clown" looking like the ocean (according to Star), and in "Hungry Larry" Jackie was originally planned to make an appearance in the episode dressed as a mermaid. On a minor note, her green eyes and blue hair stripe might also be a connection to water.
- Trouser Space: She inexplicably managed to have a skateboard and two helmets hidden under her dress during her date with Marco. And when invited to join Star and Marco at a Love Sentence concert, she somehow has three skateboards hidden... somewhere. Plus an extra helmet for Marco (presumably only refraining from pulling a third helmet out because Star magic-ed up one for herself).
- Two First Names: Her last name Thomas is also a male given name.
- What Beautiful Eyes!: Her eyes are drawn with more detail than most characters', and in Star and Marco's Guide to Mastering Every Dimension, Star says she has the second most beautiful eyes in Echo Creek Academy (first most beautiful being Oskar's).
- You Gotta Have Blue Hair: According to Star and Marco's Guide to Mastering Every Dimension, that seagreen streak in her otherwise blonde hair is natural. Although it could be a case of Unreliable Narrator from part of Star, considering that in "Freeze Day" it's shown that Jackie didn't always have it.
- Youthful Freckles: Jackie has freckles under her eyes.
Alfonzo Dolittle & Ferguson O'durguson
Ferguson voiced by: Nate Torrence
Two of Marco's friends. Alfonzo is a skinny kid with glasses and an accent, while Ferguson is a heavyset boy with red hair.
- All There in the Script: Star and Marco's Guide to Mastering Every Dimension reveals their last names and Dolittle and O'durguson, respectively.
- Ambiguously Brown: Alfonzo's name, dark skin, and accent imply that he may be Hispanic.
- Casanova Wannabe: Ferguson thinks he's a ladies man, but he's not.
- A Day in the Limelight: Issue 4 of the comics gives them one, with them following Star and Marco on an adventure again and getting a fairly prominent role. It also explains what they've been up to since Star stopped taking them on adventures with her and Marco (Fooling around with her stuff while she and Marco are out and walking the Laser Puppies.)
- Demoted to Extra: They only appear as background characters in the second season. Janna more or less takes over their role as the additional human that tags along on Star and Marco's adventures. This flat-out becomes the subject of a joke in "Collateral Damage" where Star calls on them in a crowd, saying that she hasn't talked to them all year but they're still always in the background doing their thing. We then only see their waving arms sticking out of the crowd. This was mostly due to Daron Nefcy wanting to use them as little as possible admitting that she didn't like them and that the only reason why they were added in the first place was due to the insistence from Disney to give Marco male friends. They were said to have bigger parts in Season 3, but this ultimately amounted to them appearing only once in "Sophomore Slump" with their appearance essentially serving as their proper sendoff. Still, it was more attention than what they'd received in the season prior.
- Fat and Skinny: Alfonzo's the skinny to Ferguson's fat.
- Interspecies Romance: In "Pixtopia", Ferguson fell for (and almost married) the Pixie Empress. Later Alfonzo marries her instead.
- The Load: The two are thoroughly useless. Star stopped taking them on adventures due to this.
- Non-Action Guy: They are both utterly useless in fights.
- Only Friend: In "School Spirit", Marco angrily tells Ferguson that his Too Dumb to Live behavior is why he only has two friends. With the Deep Trouble comics showing that Star has stopped considering them friends by some point prior to Season 2.
- Significant Green-Eyed Redhead: Ferguson.
- Oireland: Ferguson might be from there, as he has red hair, green eyes, freckles and a last name that starts with "O'".
- Those Two Guys: Commonly seen together.
- Throw The Doga Bone: In "Britta's Tacos" we see that they made a new group of friends after Marco left, and now their nerdiness is considered cool.
- We Used to Be Friends: The Deep Trouble comics show that a falling out with Star was the in-universe reason for them being Demoted to Extra in Season 2 — Star stopped taking them with her and Marco on adventures because of their immature behavior. She gets even more reason to distance herself from them when she finds out that they've been breaking into her room and screwing around with her stuff, and she speaks of them rather disdainfully even before learning about that. Star's offhand line about how Marco would still be hanging out with them if she were never born implies that Marco spends much less time with them. He doesn't look too happy to see that they've been breaking into his house to raid Star's room either. Finally Subverted when the episode "Sophomore Slump" reveals that Marco is still friends with them and hangs around them. Though they did get annoyed at Marco when he keeps talking about Mewni, they accept Marco's apology for his behavior and they present him with their lucky dice as he leaves for Mewni.
- What the Hell Is That Accent?: Alfonzo's accent is a little difficult to pin down.
Miss Margaret Skullnick
Margaret Skullnick is Star and Marco's cantankerous homeroom/math teacher. Star accidentally turns her into a troll in the third episode of the first season.
- All Amazons Want Hercules: She was very interested in Ludo's muscular minotaur henchman, although he ended up dumping her. She's also delighted to discover that trolls (who would now find her most attractive) are invariably super strong.
- An Axe to Grind: An ax becomes her weapon of choice once she learns about her new form in "Interdimensional Field Trip".
- Badass Teacher: Posses the physical powers of a troll, and works as Star and Marco's teacher and she easily takes on a yarn monster that's considered the most dangerous monster in the universe.
- Baleful Polymorph: Accidentally transformed into a troll by Star. Star can't figure out how to reverse it.
- Christmas Cake: Laments not being able to get a date, which was made worse when she was turned into a troll.
- Cursed with Awesome: At first she is devastated about being turned into a monster but after learning that trolls live on average 400 years (meaning she technically turned back into a teenager) and are hundreds of times stronger than a human, she changes her mind.
- Deadpan Snarker: Especially in "School Spirit", when Star asks her what is her favorite weapon, she replied with complete disinterest, "battle axe".
- Genius Bruiser: Shown to be one in "Interdimensional Field Trip"; she uses both her new trollish strength and her school-teacher wits to defeat a fearsome monster.
- I Am Who?: A slight version of this, as she never knew how great trolls are until she entered a museum of them in "Interdimensional Field Trip".
- Jerkass: She acts as jerky teacher to her students, even taking her anger out on them by giving a quiz just because the monster she liked apparently broke up with her.
- Jerk with a Heart of Gold: Despite being grumpy, strict, and disapproving of fun, she does care for her students and doesn't hesitate to rescue them from the Yarn Monster in "Interdimensional Field Trip".
- No Name Given: Only referred to as "Miss Skullnick" until "Girls' Day Out", where she reveals her first name as Margaret.
- Sadist Teacher: Mostly due to grumpiness from not being able to get a date. However, in Season 2, she became more of a well-meaning Stern Teacher after she Took a Level in Kindness.
- Silly Rabbit, Idealism Is for Kids!: She has a very cynical and pessimistic outlook on life, and seems to think it's her job to prepare her students for a dull and disappointing future.
- Stout Strength: As a troll. Turns out beneath that layer of flab is some serious muscle.
- Took a Level in Badass: After getting in touch with her new troll heritage in "Interdimensional Field Trip", she helps save the class from a string monster.
- Took a Level in Kindness: In season two, even though she still retains some of her grumpiness, she is shown to be way more eager to teach her students and more supportive of them (like in "Mathmagic", where she honestly congratulates Star for trying to solve a math problem). This is a big improvement compared to her early appearances in season 1, where she was portrayed as a miserable woman who clearly hated her job and couldn't care less about her students.
The principal of Echo Creek Academy.
- Greed: He's very easily swayed by offers of money. When Star is enrolled in the school, he chooses not to ask for documentation when her parents offer him a chest full of gold and jewels. He allows Brittney to become head cheerleader because of her father's money. So now, he has two sources of income.
- Meaningful Name: A skeeve is a creepy or immoral person, which describes him very well.
- Trademark Favorite Food: Ice cream.
She is a "mean girl" cheerleader who attends Echo Creek Academy.
- Alpha Bitch: She's the obligatory mean teenage cheerleader that opposes our quirky teenage heroine.
- Asian Airhead: She has the mannerisms and speech patterns of a stereotypical Valley Girl, and her surname suggests that she's of Asian descent. In fact, she's Chinese, but her voice actor is Japanese.
- Chuck Cunningham Syndrome: Disappeared from the series altogether after "Starcrushed", only to have one more minor cameo in the finale, a little more then two years after the former episode aired.
- Demoted to Extra: She only makes three appearances in the second season; all are brief, and only one is a speaking part. She'd completely disappear from the show altogether afterwards before returning for another minor cameo in the series finale.
- Dirty Coward: Selfishly moved to save her own ass going so far as to push her own cheerleading team out of her way (using a wheelchair user cheering mate no less!) when the Star-customized battlefield erupted into chaos.
- Eaten Alive: In "School Spirit," one of Star's traps is a dragon that eats her while she is being a Dirty Coward.
- Green-Eyed Monster: In "Brittney's Party", she is very resentful of how her guests love the improvements Star makes to her party. Her guests tell her they loved her party, but it didn't make her happy.
- Hate Sink: Clearly she isn't the most beloved character of the series, but isn't actively antagonistic toward Star (preferring to spend as little time with her as possible) enough to qualify as a proper villain, landing her in this trope instead.
- Hair Flip: When she whips her hair, it's her way of metaphorically dropping the mic after she insults someone.
- Hidden Depths: At the end of "Mr. Candle Cares", she is seen with the titular counselor, apparently discussing whether her life has already peaked. In "Collateral Damage", the distress these thoughts cause her seem to have caused her to start overeating, as she is noticeably pudgier and seen eating something clearly unhealthy.
- Hollywood Tone-Deaf: Nobody likes her singing.
- Hypocritical Humor: By insulting Star that while it's okay to be stupid in her homeworld of Mewni, she kinda lampshades her own lack of tact when she showed off her killer winning plan for the game against the Warriors team (trying to distract the visiting team by shaking the cheer squad's booties at them). Only highlighted more so by the fact she let an injured teammate who can't even shake her booty onto the field.
- It's All About Me: Needless to say Ms. Wong didn't take it very well when Star contradicted her plan to win the upcoming game against the warriors.
- Jerkass: While she surprisingly has avoided initiating any conflict so far, she compensates with a rude and hostile attitude toward everyone she interacts with.
- Jerkass Has a Point: To be fair, some of her complaints about Star are somewhat justified. In "School Spirit" Star bursts in and behaves randomly in her training session and in "Brittney's Party" Star and Marco are uninvited guests that takes over her party and then endangers everyone with their monster enemies. Though nobody but her was enjoying the party until they arrived, and Star misunderstood her thinking she was invited.
- Kick the Dog: Takes advantage of Sabrina and her injury in order to save her own life. Again played with when she hair whips a laser puppy.Star: Not cool.
- Pet the Dog: Lets Sabrina join the cheering squad in the game despite her injury.
- Popular Is Dumb: The best this dumbbell diva can come up with for a big game win against a rival school team is distraction via mass produced rump shakeage produced by herself and her cheering squad. It doesn't work.
- Put on a Bus: After "Starcrushed", only to appear one more time for a brief cameo in the series finale.
- Rapunzel Hair: Her hair reaches down to her waist.
- Rich Bitch: She's head cheerleader because her father made a "sizable" contribution to the school.
- Ship Tease: With Justin in "Collateral Damage".
- Sitcom Arch-Nemesis: One-sided on her side to Star.
- Spoiled Brat: Daddy buys her way into higher clique status? Check. Arrogant, selfish and mean spirited to pretty much everyone? Check. Treats those around her whom she deems beneath her notice with spite and disdain due to her upbringing, be they equally popular or just regular folks? Do you really need to ask?
- Ungrateful Bitch: Star makes her party a success, but she doesn't care, she's just upset that she got upstaged.
- Unknown Rival: Hates Star for being as popular as her, if not more so. Star is completely oblivious to this.
A student at Echo Creek Academy and quarterback of the Awesome Opossums team.
- All There in the Script: Star and Marco's Guide to Mastering Every Dimension reveals his last name as Armberg.
- Catchphrase: "Star Butterfly rules!"
- Demoted to Extra: Well, he was always an extra, but he appears even less in Season 2.
- Dumb Blonde: He repeatedly tries to touch a sparking electrical thing during a field trip, including with his tongue.
- Dumb Jock: Good at sports, not very bright.
- Fanboy: Of Star, as evidence by his Catchphrase.
- Keet: He's very upbeat and energetic.
- Lovable Jock: The school's quarterback and a pretty nice guy.
- Lucky Seven: His uniform number is "7".
- Nice Guy: He's always a nice fella towards others.
- One Steve Limit: Averted. He shares his first name with Love Sentence singer Justin Towers.
- Ship Tease: With Brittney in "Collateral Damage".
- Top-Heavy Guy: Justin has a moderately heavy build and is on the Awesome Opossums Football team.
- Trademark Favorite Food: He likes to eat oysters, as shown in "Brittney's Party".
A musician who goes to Echo Creek Academy. Star has a crush on him.
- Accidental Misnaming: Oskar repeatedly refers to Marco as "Mango" when talking to Star in "Starcrushed".
- Blinding Bangs: His eyes are usually obscured by his hair. Once he gets a haircut, his huge eyes are exposed.
- Broken Pedestal: With her crush goggles for Oskar now gone in "Starcrushed", Star has started to realize he's an idiot.
- Burger Fool: In Season 4 he's working at a taco place.
- Character Blog: He has a Twitter, the username of which was revealed in Star and Marco's Guide to Mastering Every Dimension.
- Companion Cube: He's almost never seen without his keytar and his car.
- Cute Little Fangs: Two of them. Since he's (presumably) human, it's unknown why he has them.
- The Ditz: Oskar isn't really the brightest guy around, from being oblivious to hazards to being rather poor at remembering names. Even Star realizes now what an idiot he is.
- Dreadful Musician: His keytar playing is abominable. Star loves it, though. Downplayed in "Mewberty", his keytar playing has improved, (By which we mean he doesn't cause people to writhe around in agony but his singing and lyrics could still use some work.
- Drives Like Crazy: In "Star On Wheels", much to Marco's terror when he gives him a lift, Oskar drives extremely fast and barely pays attention to the road.
- Early-Bird Cameo: He is briefly seen amongst a crowd of students in "Match Maker".
- Hidden Depths: The song he writes in "Mewberty" indicates some obvious mother issues. One of the lines includes "I don't like your boyfriend, mom."
- Important Haircut: Oskar's new hairstyle in "Starcrushed" makes him look much less cool.
- Nerves of Steel: He barely reacts to the Mewberty-powered Star pulling him and his car up into the sky. Even when he crashes back down to Earth, he shows no signs of trauma, giving Marco a nonchalant "S'up?" In "Blood Moon Ball", his only reaction to Tom arriving at school is to tell him he's parked in a handicapped space.
- Noodle Incident: Principal Skeeves says he has "a record".
- Odd Friendship: He gets along quite well with Glossaryck during "Star On Wheels", with the two of them goofing off and making music while Marco's trying to get them to focus on rescuing Star.
- Out of Focus: After "Girls' Day Out", he suffered a long absence from the series. This is somewhat explained in "Starcrushed", where he mentions dropping out of school to pursue his musical interests.
- Parent with New Paramour: He apparently takes issue with his mother's boyfriend, according to one of his song lyrics.
- Satellite Love Interest: His only role in the show is someone Star's crushing on. The most we see of him is sitting on his car playing his keytar badly.
- He manages to have some decent interaction with Star in "Starcrushed", but not much is added to his character.
- Suckiness Is Painful: In his first appearance, his music causes people to writhe on the ground in pain, except Star.
- Unrequited Love Switcheroo: When her crush on Oskar faded, Star isn't very thrilled with seeing Oskar during the events of "Starcrushed". Meanwhile, when Star held his fist, Oskar was clearly flustered, and he later expresses a desire to hang out with her in the same capacity that Marco usually does.
- What Beautiful Eyes!: Whenever Oskar's eyes are shown, they have eyelashes and lots of highlights in what is most likely a parody of this trope. "Star on Wheels" confirms that this isn't a Crush Filter on Star's part; his eyes really do look like that all the time, and they are huge.
A student at Echo Creek Academy. As her name suggests, she is a huge fan of Star Butterfly.
- Ambiguously Bi: She's pretty clearly a Schoolgirl Lesbian for Star, but in the second live chat, she mentions that her favorite version of the alternate universe versions of Star in "Mathmagic" is the male one. The "FanCo13 LIVE" chat held after "Starcrushed" aired also had her calling Marco very handsome in his prince costume from "Face the Music".
- Audience Surrogate: Where to begin? She is called StarFan13 for a reason. Star's such a likeable character to have that many zealous fans in the audience. She's a hardcore Starco shipper, which is very much a majority of the fandom. If there's anyone who best personifies the audience, it's her.
- Clingy Jealous Girl: In the second StarFan13 LiveChat, she briefly pulls out some paper cutouts of Star and Marco to play out Star saying, "Marco, you're lame and StarFan13 is really my best friend," showing hints of jealousy toward Marco.
- Creator Cameo: She is voiced by the creator of the show.
- Curtains Match The Windows: Brown hair and eyes.
- A Day in the Limelight: Hosted a live animated chat session on Facebook shortly before the premiere of the midseason finale. She hosted a few more later on, including a joint one with Marco titled "FanCo13 LIVE" after the season 2 finale.
- Fangirl: Of Star Butterfly.
- Hypocritical Humor: According to her live streams, she's read all of Star's secret journal, but she won't reveal anything from it because that would be an invasion of privacy.
- I Want My Beloved to Be Happy: Despite the fact that she's in love enough with Star to change her name, she's admitted to being a Starco shipper.
- Nerd Glasses: StarFan13 wears red square-rimmed glasses.
- Only Known by Their Nickname: Even in an episode where she isn't just a gag, she is only referred to as StarFan13. And ''Star and Marco's Guide to Mastering Every Dimension'' shows her name in the the Echo Creek Academy yearbook as Starfan13, possibly implying that she's legally changed her name."I don't have a real name. I gave that up long ago."
- In the first live stream chat, she even claims that she's never had any other name.
- Schoolgirl Lesbian: She has a huge crush on Star, though her affection can kinda veer into Psycho Lesbian territory as it's not clear if she wants to date Star or be Star. It could very well be both.
- Shipper on Deck: In "Starcrushed", she smiles excitedly when Star admits to having had a crush on Marco, and is disappointed when Star claims that she doesn't anymore. And then when Star confesses her love to Marco, Starfan faints. In the joint Marco and StarFan13 live chat after the episode aired, she admits to being a Starco shipper and says she's written Starco fan fiction.
- Ship Tease:
- Her Stalker with a Crush behavior toward Star is never shown to be unwelcome, and the Stalker Shrine dedicated to Star that she keeps in her locker apparently has a reciprocal counterpart dedicated to StarFan13 in Star's own locker.
- The live stream chat after "Starcrushed" aired that was hosted by Marco and StarFan13 simultaneously was named "FanCo13 LIVE" (in much the same style as "Starco" is named), and in it, she tells Marco that she thought he looked very handsome in the prince outfit he wore in "Face the Music".
- Skirt over Slacks: Her way of emulating Star's usual style.
- Spell My Name with an "S": A minor detail compared to the confusion about the hyphen in Jackie's name, but various bits of official material like the live chats give her name as StarFan13, while her name in the Echo Creek Academy yearbook is spelled Starfan13, without capitalizing the "f" in fan. It's possible that one of them is her legal name used in the yearbook while the other is the Internet username she goes by.
- Stalker with a Crush: On Star.
- Stalker Shrine: Her first appearance has her showing Star the Stalker Shrine she has in her locker dedicated to pictures of Star. Bizarrely enough, Star's locker is similarly plastered with pictures of StarFan13 herself.
A cheerleader at Echo Creek Academy who is ridiculously accident-prone.
- All There in the Script: Star and Marco's Guide to Mastering Every Dimension reveals her last name as Backintosh.
- Born Unlucky: Definitely. She is always viable to accidents and injuries everytime.
- The Chew Toy: Virtually every episode she appears in has her suffers Amusing Injuries in some way. This is taken Up to Eleven in the season 2 finale "Starcrushed", where she shows up at the end of the school year party with casts on both of her hands and both of her feet.
- Creator Cameo: She is voiced by the creator of the show.
Other residents of Echo Creek
A foreign exchange student from Scandinavia who lived with the Diaz's before Star came to Earth, and comes for a visit in "The Other Exchange Student". His monopoly on the Diaz's affections drives Star to extreme jealousy.
His real name is Charlie Booth, and he actually hails from the drab town of Bakersfieldville. His dream in life is to become a chef so he can bring some flavor and color to his hometown, and he travels the country posing as foreign exchange students to various families so he can try his recipes on them.
- The Cameo: He briefly appears (in his "Francois" guise) in "Freeze Day" and again to attend the baby shower in "Marco Jr".
- Critical Research Failure: Used In-Universe to foreshadow that he's a Fauxreigner as he thinks Scandinavia has penguins (that apparently everyone has one) and polar bears. And that's on top of thinking Scandinavia is a single country and not just a region consisting of several countries. Also thinks that lederhosen and dirndls are Scandinavian, as seen when he gives Marco a Nintendo game called "Lederhosen Tycoon". Also gives the Diazes wooden shoes/clogs. In fact, Scandinavians have puffins, lederhosen is German and clogs are Dutch.
- Fauxreigner: Turns out to be from a boring town close by and pretends to be a foreign exchange student to practice his chef skills. He even does the same schtik to another family, this time as French.
- Foreign Exchange Student: From Scandinavia. Or so he would have the Diaz's believe. He is in actuality a full blooded American who poses as various nationalities to trick families into taking him in so he can hone his skills as a chef by practicing various regional (for whatever nationality he's posing as) dishes on them.
- I'm a Humanitarian: What Star believes him to be given his insistence on feeding the Diazes his meatballs. Turns out to be unfounded, since he is really a traveling cooking student and is trying his recipes on the Diazes. Although he never explained measuring the Diazes while they slept.
- Nice Hat: He wears a blue, red and turquoise beanie.
- Norse by Norsewest: Claims (As Gustav) to not just come from "The country of Scandanavia" (Which is not so much a single country but a region encompassing several nations), but a particularly stereotypical version (mainly Sweden), no less.
- Omniglot: Has a working knowledge of at least two foreign (to America) languages, and possibly more if he has other nationalities that he passes for.
- Remember the New Guy?: Not just for himself, since he isn't alluded to at all before his premiere episode, but also for a whole host of foreign exchange students that the Diazes have taken in, as evidenced by a wall covered in their photos.
- Slasher Smile: While he doesn't turn out to be a cannibal, he still makes this rather psychotic face. Is it really hard to blame Star for that assumption?
A bratty eight year old who takes karate alongside Marco.
- Amazingly Embarrassing Parents: Jeremy really doesn't take to his mom embarrassing him.
- Bling of War: He owns a gold, jewel-encrusted knuckleduster.
- Bratty Half-Pint: Very much so. Even his parents aren't safe from his attitude, or rather because they embarass him too much.Mrs. Birnbaum: We love you, son!
Jeremy: SHUT IT, MOM!
- Chuck Cunningham Syndrome: Completely disappeared from the show after "All Belts Are Off".
- Combat Pragmatist: He hides a knuckle duster under his glove before his match against Marco.
- Enfant Terrible: He came to visit Marco on Picture Day just to give him a black eye.
- Epic Battle Boredom: In "All Belts are Off" Jeremy made a big egotistical intro then quickly and arrogantly defeated a yellow belted opponent. This actually bored the Grandmaster and it had put him to sleep. When the Grandmaster woke up, he assumed that the event was over and quickly left despite Jeremy trying to tell him that he wasn't finished and that he had just started.
- Grumpy Bear: According to Preston Change-o, Jeremy had very little joy to begin with, hence why his joy-sucking magic had affected Jeremy so strongly despite only taking a small amount.
- Hate Sink: He introduced himself in "All Belts are Off" in the most egotistical and self centred way possible such as involving singers, demanding his photo to be taken and expecting the audience to applaud him. Due to this, the audience quickly hated him and left the dojo as soon as the Grandmaster left. Sensei goes so far as to call him a "toilet" behind his back.
- Kick the Dog: The worst thing he's ever done is pull a sick, demented prank on a disabled passer-by involving a glued $100 bill with rainbow-colored turd on it, causing the poor guy to struggle, and lose his glasses in the turds. And it was that guy's birthday.
- The Napoleon: He may be shorter than Marco, but he still attempts to intimidate him and lord over him.
- Pick on Someone Your Own Size: Inverted. He goes out of his way to mock and annoy Marco, despite their differences in age, and relishes the opportunity to beat him up in their karate match.
- Pyrrhic Victory: Jeremy may have been selected to represent the Dojo, but he ends up ashamed when his mediocre display bores the Grandmaster to sleep and they only barely get his approval for certification. Plus, the entire audience sees firsthand what a conceited brat he is and he gets abandoned by everyone but his butler once the karate demonstration is over.
- Put on a Bus: Never appeared on the show again after "All Belts Are Off".
- Screw the Rules, I Have Money!: His karate rank is only due to his parents buying the belts for him. His parents are also the main source of income for the dojo, which is why Jeremy was chosen to represent the Dojo despite Sensei knowing that Jeremy is terrible at karate.
- Sitcom Arch-Nemesis: He is this to Marco, just as Brittney Wong is to Star.
- Spear Counterpart: Jeremy is practically a younger male version of what Brittany Wong is to Star — a talentless, spoiled, rich brat whom nobody likes and whom hates their much nicer classmate who happens to be a hero (Star for Brittany, Marco for Jeremy). However, Jeremy doesn't just flaunt his status and judge others based on what HE thinks of them—he actually goes the extra mile and pulls sick, demented pranks on others and is a dirty cheater, all of which make Brittney look like a nice girl.
- Spoiled Brat: His parents buy him anything he wants.
Marco and Jeremy's karate instructor who runs a dojo out of a local Echo Creek mini-mall. His chiseled physique and spry athleticism belie a monumental amount of immaturity.
- All There in the Manual: Star and Marco's Guide to Mastering Every Dimension reveals his name as Brantley.
- Almighty Janitor: He's only, just recently, actually ascended to red belt (which is, essentially, still just the martial arts equivalent to grade school). That said, he's good enough to blow enough wind to put a fire out with a palm strike.
- Ascended Extra: He becomes a recurring character in Season 2, and basically seems to be Marco's best friend after Star.
- Big Ol' Eyebrows: He has thick eyebrows.
- Burger Fool: In season 4, it turns out he'd been working at Britta's Taco for the last half year. If this was to supplement his income running the dojo or replace it after it closed down is unknown.
- Charles Atlas Superpower: In "Trickstar", he's able to put out a huge fire with the wind generated from a palm strike.
- Curtains Match The Windows: He has brown hair and eyes.
- Everyone Calls Him "Barkeep": Nobody refers to him by name, only by his position.
- Fake Ultimate Hero: Before Season 2, he was actually a green belt in karate just like Marco because he never actually finished the training course and his mini-mall dojo only becomes legitimately certified several episodes later.
- Family-Unfriendly Aesop: In-Universe, he learned from watching kids shows that Poor Communication Kills is how friends work.
- Incompletely Trained: The Sensei never finished his training and never made it past a green belt. Only later on does he advance to a red belt and become certified much later.
- Intergenerational Friendship: Sensei Brantley becomes friends with his karate student, Marco. In fact, it seems that, after Star, Sensei is Marco's best friend.
- Manchild: He's a man in his late 30s who learns much of his wisdom from in-universe cartoons.
- Momma's Boy: He lives in his mother's house.
- Money, Dear Boy: In-Universe. He lets Jeremy get away with much of his terrible behavior because his parents keep his dojo funded. However, the Birnbaums are too witless to exert any real power over the establishment and once Marco learns about the scam, he more-or-less approves of Sensei filching them for all they're worth.
- Poor Communication Kills: He learned from children's shows that "doing hurtful things to each other without explaining why, because they know their friends will understand," is something friends do. This is why he wasn't upfront and honest with Marco about why Jeremy got chosen over him.
Bon Bon the Birthday Clown
A beloved clown that used to live in Echo Creek until he died a hundred years or so before the events of the show. His signature trick were candles that lit themselves again every time you put them out, and supposedly like them, he will "come back" on the hundredth anniversary of his death.
- Back from the Dead: He promised to come back on the 100th anniversary of the day he died. Star and Janna planned on holding a dead clown séance to greet his ghost.
- Back for the Dead: In-Universe, he gets sucked into a vortex that Star used against Ludo shortly after his ghost returns.
- Fatal Method Acting: He initially died after his trick candles for the mayor's birthday party exploded in his face.
- Non-Ironic Clown: He was an entertainer.
- Red Herring: His name is the title of the season two mid-season finale. The episode actually focuses on Marco's date with Jackie and Star's jealousy over it, and the villain instead turns out to be Ludo. He actually does show up towards the end, as a ghost Only to be sucked into a black hole without contributing anything to the story.
- We Hardly Knew Ye: Falls victim to this. Twice. In the episode intro, he dies in a tragic accident involving trick candles, not two minutes in, but he promises on his death bed that he will be back eventually. And he does come back! Only to get caught in the crossfire of Star's and Ludo's fight, where he's sucked into a black hole.