The Hero of the Mushroom Kingdom leaps into action once again to save the world. He's, unsurprisingly, the Jack-of-All-Stats of the game and he specializes in jump and fire magic.
Badass Mustache: Mario's mustache earns admiration from his fans and scorn from his enemies at various points in the game.
Dude, Where's My Respect?: Generally averted. Almost everyone you meet knows who Mario is, and they treat him with the respect deserved by one who saves the world for a day job. He's so famous in fact, a Snifit in Seaside Town considers a jump from him as accurate identification.
Evolving Attack: Though he learns six magic attacks, they're basically just powered up versions of the two base attacks: Jump, Super Jump, Ultra Jump, and Fire Orb, Super Flame, Ultra Flame.
His basic jump attack also gets more powerful as you use it more.
Good Old Fisticuffs: His base unarmed attack and a few of his weapons are punch combos.
Kleptomaniac Hero: You can get called out on it - after assisting a man to his house in Rose Town, he asks if the treasure chests in his house are safe. If you tell them someone took them he's Genre Savvy enough to realize only Mario could jump high enough to get them, and you have the option to come clean about it.
Narrative Shapeshifting: He can even walk on air while doing it. He's a talented storyteller!
Playing with Fire: Those of his magic attacks that aren't Jump attacks.
Mallow
"I’m Mallow from Tadpole Pond. I’m a frog, but can you believe it? I can’t jump. Embarrassing huh?"
A "tadpole" from Tadpole Pond who came to the Mushroom Kingdom on an errand, to his utter shock and horror he's told he isn't a tadpole, and joins Mario to find his real family. He's the resident Squishy Wizard who has lots of magical abilities deriving from the weather.
Badass Adorable: He looks like a walking marshmallow with a cheery smile and a childlike disposition. He's also a magic slinging badass whose weakest attack is summoning lighting storms from cloudless skies!
Boring, but Practical: Thunderbolt is the only Herd Hitting Attack you have access to until around Land's End when other people begin to learn them, and with a timed hit and good training to Mallow's magic it's pretty effective. The only other attack up to then that can hit all enemies is Bowser's Terrorize, but his magic attacks are nowhere near as strong as Mallow's.
Informed Flaw: Everyone, including Mallow himself, says he's sort of a crybaby, but he only cries three times in the entire game, and all for pretty understandable reasons. Granted, that's three more times than any other character, so he may have a point.
Interspecies Adoption: Mallow was adopted by Frogfucious, and grew up believing he was a "Frog that can't jump".
Oblivious Adoption: He doesn't realize he's not a frog. No one else in his hometown seems to notice either.
Royals Who Actually Do Something: Granted, he doesn't realize he's royalty for most of the game. But he does continue on with the quest after learning it.
A representative spirit from Star Road sent to find the Star Pieces, he takes up residence in the body of a doll and makes it grow to life size to use as a body. He's quite a Glass Cannon and Fragile Speedster.
"I'm gonna do something I may regret later...! But I'm gonna let you join the Koopa Troop. You can thank me later..."
The leader of the Koopa Troop and Mario's archnemesis got booted out of his home when Exor crashed into it. Now he's decided to let Mario join the Koopa Troop to work together to smash Smithy. He's primarily a physical attacker and Mighty Glacier. His magic is weak compared to Mallow's or Geno's, but it can cause Standard Status Effects.
Benevolent Boss: Yes, Bowser of all people is shown as this. The handful of his former henchmen you meet up with over the course of the game apologize for abandoning him, but Bowser is universally forgiving of them, wishes them well in their new lives, and they're very willing to help him out.
Fastball Special: The Hurly Gloves involves chucking Mario at an enemy. Judging from the way Mario is flailing his arms around when Bowser throws him, he's never expecting it either.
Foe Yay: Play your cards right in Marrymore and you can get him to kiss Mario!
In the same scene he asks Toadstool for a kiss when she promises one to Mario for rescuing her.
Pet the Dog: When he frees a Chain Chomp in Booster's Tower that Booster had locked up because she bit him. Gets more moments as he meets back some of his former troops across the game.
Slave to PR: Though he's been ousted from power, he still goes through great lengths to put on an air of power and intimidation. Several points in the game we see his inner musings on how to go about helping Mario and/or asking Mario for help while still saving face as a villain.
"I'm the biggest, baddest brute around, and don't you forget it. But if Mario hears that I've been kicked out of my own castle... My reputation will be ruined! Even I have an image to keep up you know!"
Still The Leader: Inverted. He is the fourth to join your group... and the only things he can influence are combat and the mooks inside his own castle.
Summon Magic: Though his magic attacks are the worst in the game, they fall into this category with him calling Boo, Mokura and Mecha-Koopas to attack opponents.
The Princess of the Mushroom Kingdom has been kidnapped again, but this time she isn't content to sit back and let Mario do the heroism once he rescues her. She's the White Mage of the group, thus, your primary healer.
Combat Medic / White Magician Girl: She starts out with okay weapons, but her healing is invaluable. Once her stronger weapons and spells appear, she's one of the best characters.
Rebellious Princess: She's not very confrontational about it, though; she dresses up her grandmother as herself and floats out of her window with her parasol to join Mario's group.
Wake Up Call Boss: He's the second mini-boss in the game, and following the first you naturally wouldn't expect much. This line of thinking proves fatal if you thought to just breeze though Bandit's Way without leveling up Mario and Mallow.
Belome
"Ooh! Room service has been kind to me! Where's my bib?"
Another monster of ambiguous design who guards the Kero Sewers, he has a huge tongue and an appetite to match.
Enemy Summoner: In the second battle he can clone party members by tasting them.
Giant Space Flea from Nowhere: His appearance in the Kero Sewers is foreshadowed, with Mallow saying Frogfucious warned him about Belome. However, his reappearance in Land's End in a golden underground temple dedicated to him was a bit out of left field.
Load-Bearing Boss: Defeating him in the Kero Sewers causes the sewers to flood as the floodgate opens. Justified as he was standing on the switch keeping it shut.
Punchinello
A bomb-happy...thing lurking in the Moleville mines, he attacks Mario to try and get some recognition.
Attention Whore: EVERYTHING he's doing is attempt at being famous.
Snifit 1: Booster really, really, REALLY likes beetles! Be he can't catch his own. Snifit 2: That's right, he's busy keeping the princess from the sky entertained. Snifit 3: So we're catching beetles for him.
Cloudcuckoolander: He lives in a giant tower full of toys, rides around on an electric train set, believes that Toadstool's tears are signs she's "sprung a leak", and he has to have his Snifits explain to him what a party is (and judging from their description, they're not entirely sure themselves).
"My bride-to-be is chanting 'MARIOHELPMEMARIOHELPME'. Is she showing her happiness?"
"I wonder when my next bride will fall from the sky?" This happens.When Valentina flies off, she has to land somewhere eventually...
Cool Train: Consider the unseen rail system he must have to be able to ride it up and down the tower.
Train Fu: If you mess up the final minigame in his tower you face him and all his Snifits together, and his strongest attack is to jump on his train and ram it into a party member.
Everything's Even Worse with Sharks: Subverted. He isn't a bad guy at all really—he hands you the Star Piece after defeat and helps prevent Yaridovich's escape so that the party can fight him and get the Star Piece back. Also, Mario invaded his ship to find the Star, so when you think about it he was just defending himself and his prize rather than being openly hostile.
"Will you accept my challenge? You will enter combat against me?"
A knight from another dimension, he planned to conquer Mario's world but found it isn't suitable to his kind, so he departs, but first asks Mario for a battle. He attacks with four elemental Crystals.
Art Shift: A big clue that he's not of this world is that he uses a flat 2-D sprite that never moves (it just floats around), while all other enemies in the game use 2.5-D isometric sprites that walk in place.
Which itself is a shout out to Final Fantasy IV's Golbez, who was named after a type of fly. Oh, and is possibly the most competent Final Fantasy not-quite-villain.
Musical Nod: The Prelude and victory fanfare from the Final Fantasy series in general, and the track that plays when you fight him is Final Fantasy IV's boss theme.
"Listen up, gang! These guys are gonna put a stop to OUR party! Are we happy about this?!"
The first member of Smithy's Gang, he and an army of Shypers invade the Mushroom Kingdom and turn the castle into their base while Mario is off tracking down Croco in Bandit's Way.
Dangerously Genre Savvy: Unlike most of his cohorts, Bowyer doesn't find it fair that the party gangs up on him three-on-one. He fixes the problem by randomly locking one of the player's button commands, often preventing them from using healing items or attacking, depending on which command he uses.
Meaningful Name: "Bowyer" is the term for a person who makes, maintains and repairs bows and arrows.
Puzzle Boss: A subtle variation, he locks whatever button command the player uses most, so the trick is to confuse him and mix up your attack patterns.
"I'm such a genius, it scares me sometimes. No wonder I'm so important!"
A creature wielding a spear, he splits into copies of Mushroom kingdom citizens and collectively poses as the citizens of Seaside Town to trick Mario into retrieving the next Star Piece for him.
Insufferable Genius/Smug Snake: Even when he's pretending to be Mushroom citizens, Yaridovich is quite the dick to Mario. He only gets worse when he reveals his true form.
Lost Forever: Though it's questionable just how useful they are, the rather unorthodox items sold in the shops under Yaridovich's watch cannot be bought anywhere else.
Meaningful Name: His name is a combination of "Yari", the Japanese word for "spear", and "ovich", a traditional Russian naming convention.
Paper-Thin Disguise: Besides the Musical Spoiler of the "troubled town" theme playing when you first visit, it's quite obvious there's something more than a bit strange about Seaside Town when Yaridovich is playing as its citizens.
Combined Energy Attack: An evil version; After each of them is individually defeated, they pour their energy into the Blade so that it can fire the devastating Breaker Beam.
Dangerously Genre Savvy: Whenever a Star Piece is located it rises up, spins around Mario's head for several seconds and then drops into his hands. The Axem Rangers snatch the star during the process, leaving Mario to look around wondering what happened before he notices them.
Flash Step: Axem Black moves so fast he leaves multiple images as he sweeps in to attack. Of course, given that the game is a turn-based battle system, this is mostly just Rule Of Cool, although it can help illustrate why he's able to attack in-between your turns...
Shoot the Medic First: Axem Pink heals her allies, she has the lowest HP, and she can turn the party into Mushrooms. Invoking this trope is highly advised.
A giant sword that crashed into Bowser's castle and shattered the Star Road, it's mouth acts as a gateway between the Mushroom Kingdom and Smithy's world.
Climax Boss: Though all the gang members are fought at the end of the respective worlds, Exor is notable for being the final boss of the Mushroom Kingdom before The Reveal that he's just a gateway to Smithy's world and the game continues on there.
Cognizant Limbs: "Exor" is actually the tip of the sword's handle, the other targets in the battle are the two eyes and mouth, the latter of which is named "Neosquid" for some reason.
Fascinating Eyebrow: A rather odd instance, this is the animation used for the eyes when they attack.
Fireball Eyeballs: Exor's "face" on the hilt, not the two larger ones.
Non-Lethal K.O.: Its eyes and mouth can't be permanently killed, they sit out a few turns then regenerate.
One-Hit KO: A perfectly timed Geno Whirl can kill Exor in one hit, the only boss vulnerable to this.
The Walrus Was Paul: Exor's mouth is named "Neosquid". No explanation for this is provided.
Smithy
"Why don't you give me YOUR stars. Why, then I could easily conquer this world! Then we could get rid of all wishes, and create a world filled with...WEAPONS!!!"
The Big Bad who wants to Take Over the World with an army of anthropomorphized weapons, he works from a dark factory in another world using Exor as a gateway into the Mushroom Kingdom.
Cognizant Limbs: In the final battle his body and head are two different enemies, though the lower body can't be killed off for good and is so weak it's little more than a distraction from his head.
Death from Above: Sledge, which calls a giant piston to stomp the party.
Enemy Summoner: Smelter spits out a blob of goo, Smithy pounds it into a Mook to assist him. Rinse, repeat. And, if the conveyor belts running out of his lair are an indicator, Smithy also personally created every other member of the Smithy Gang himself. Thankfully, those Machine Made copies of the gang's elite members aren't called in to help him during the final battles.
Fire, Ice, Lightning: The Mask Head is weak against ice, the Tank Head is weak against electricity, and the Treasure Head is weak against fire.
Flat Character: He's given very little backstory and personality besides being a distant Evil Overlord who wants to conquer the world. He says his desire is to fill the world with his weapons, and he actively hopes the Star Road is not repaired and that wishes will continue to go ungranted, but aside from The Evulz he doesn't express much reason for doing what he does.
Hidden Villain: He's never seen in person until the final battle. In fact if you didn't know better, a player could easily mistake Exor as Smithy, since Exor isn't named until the battle with it.
Unstoppable Rage: The main reason he goes One-Winged Angel is that he's so utterly pissed off that Mario and co defeated him in the first round. The fact that he also unwittingly broke his own factory in his rage and forced him into what seems to be a boiler room also doesn't help quell his temper either.
Vile Villain, Saccharine Show: The Mushroom Kingdom and outlying regions are, as you'd expect, colorful and lively with all manner of cartoonish creatures, and even the members of the Smithy Gang fit with this atmosphere...then you get to Smithy's Factory◊.
