There are many characters in Super Mario RPG: Legend of the Seven Stars, many of which are memorable for a special trait. Here is a list some of them, at the time of Booster's Tower. (This time frame will be expanded soon)
The hero of the Mushroom Kingdom. He originally set out to save Toadstool from Bowser, but ends up having to save the world from the invasions of the "Smithy Gang" and reunite the Star Pieces.
HP Rain (swappable)
When his Frog Coin was stolen, Mallow was comforted by Mario, and the two set out to retreive it. Mallow acted as an ally, but soon became Mario's partner in saving the world!
Actually known was "heart note ! ?", this fellow was a star who possessed a doll named Geno. He came down to the lower realms of the world to retrieve the Star Pieces and rebuild Star Road. Since Mario had already collected two, he decided to help him on his journeys.
With plans to reunite with his Koopa Troop failing, Bowser decided to let Mario, Mallow and Geno join his army, so he can reclaim his castle. He then helps them throughout their journey.
Whilst not fully playable, Yoshi is a ridable dinosaur who resides on Yo'ster Island. Mario tries to help him win the Mushroom Derby against Boshi to bring back the fun on the island!
As usual, Peach is the damsel in destress. This time, she is known as Toadstool (probably as it is an old game) and the situation is much more complex. As Mario was about to rescue here, a large crash sent them flying. Toadstool happened to land in a tower not far from Moleville, and is rumoured to be the bride of a guy called Booster... As we progress through the game, things will hopefully become clearer.
Toad is a forgetful young chap in this game, but is actually quite helpful, acting as the tutorial character of the game. He introduces Mario to new gameplay mechanics and also helped him on his adventure for a bit.
The leader of the toads who appears to be a lot like a prototype Toadsworth. He worries about the princess and begs Mario to save her. He isn't very brave, however, cowarding in far half the time.
A nigh-omniscient frog and Mallow's adoptive grandfather. He lives on a small island in Toadpole Pond and is the leader of the tadpoles. He informs Mario of the "Smithy Gang"'s invasion and requests that he and Mallow save the world from the armies of living weapons. He also helps Mario out whenever he gets stuck.
Whilst occasionally an enemy, Lakitus are also seen as allies. One is a friend of Frogfucius and another, or perhaps the same, lives in Rose Way and gives Mario a mushroom if he manages to beat all the Shy Guys he hooks up on a rope.
A female Chain Chomp who was attached to a wooden block after accidently biting Booster. She was locked in a room on a high ledge, but eventually Mario and co. arrived and freed her. She then assists them in battle as Bowser's weapon, initially joining so as to get revenge on Booster.
The King of Koopas. He starts of as the central anatagonist, but that all changes when his castle on top of Vista Hill is invaded. Bowser appears throughout the game with some of his minions, trying to regroup his troops together after they were scattered across the world. He eventually joins the party.
A chain chomp who keeps the chandellers up in Bowser's Keep. He doesn't attack, but has to be defeated to get rid of Bowser.
A large Hammer Bro. who treats his hammer like a living object. He sets up an invasion of Mushroom Way in the name of the Koopa Troop, blocking the path to the Mushroom Kingdom. As such, Mario engages in battle with him and emerges victrious. After the battle, Mario takes his hammer and uses it as his own weapon.
A reoccuing boss. This crocodile is similar to most thieves in that he is a coward, running away from Mario and co. after stealing from them. He stole Mallow's frog coin, and later all of Mario's money. He is very weak to fire, and claims to always carry bombs with him. He gets a little braver as the game progresses, but stays a crock.
With his army of Shysters, Mack invaded the Mushroom Kingdom. He is a giant, pyrokinetic knife who is part of the "Smithy Gang" and holds possession of the blue Star Piece
This is a monster which was rumoured to reside in Kero Sewers. Mario and Mallow must venture though these sewers, and come across the beast. Belome has a huge appatite and finds it hard not to eat people. They also guard the flood gates of the sewer.
A giant bow who find it hard to form grammatical sentences. He fires paralysing arrows known as Aeros, and can also manipulate the attack stragery of foes using his purple blocks. He was given the green Star Piece in the Forest Maze and tries to take over Rose Town, being part of the "Smithy Gang"
A little-known fellow who knows a lot about bombs. He has four types of bombs at his disposal, but throws tantrums when things don't quite go the way he planned. He wanted to defeat Mario so he could become famous. He may have also been in possession of the orange Star Piece, or at least hands about in the same location as it's crash site.
A fast, arrogant Yoshi who lives on Yo'ster Island. Upon winning the Mushroom Derby, he decided to change its rules, taking th fun out of it. He is Yoshi's rival, who has to be beaten in order to bring the races back to their former glory!
A giant, living sword who crashed into Bowser's Keep on Vista Hill, starting off a new adventure. He claims ownership over the world in the name of the "Smithy Gang" and his appearance marked their first invasion!
A strange man who lives in a large tower. He usually allows people to play with him and his snifits in his twisted manor. However when Peach fell from the sky into his tower, he became busy with is plan to marry her, becoming much more hostile to his guests. He acts as a sort of villain, yet not directly.