Adaptational Heroism: The original version of Sun Wukong kills wantonly as soon as he is not within the presence of the Tang monk. For instance, during a period when he was dismissed by the Tang Monk, he wiped out a group of hunters who killed many of his fellow monkeys. Popular adaptations had him sparing the hunters, as well as merely injuring minor antagonists instead of killing them as he did in the original.
Almighty Janitor: Before he finally became a Buddha, his official job in Heaven was a stableboy, until he found out how unimportant the job was (i.e. the very lowest post in the hierarchy) and stormed off back to earth. As a side-effect, all Earthly horses love and admire him, because they can sense he was once a celestial groom.
Arrogant Kung-Fu Guy: No matter who you are, he is a better fighter than you and will demonstrate if you say otherwise.
Exact Words: He doesn't like following Sangzang's orders so he gets around them with this trope. For example, Sangzang said "Never kill anyone." So when a group of greedy monks tried to kill them both to steal Sangzang's cossack, Monkey didn't kill them. Instead he fanned the flames of the fire they started to ensure their monastary burned down.
Folk Hero: In real life for bringing back buddhist scriptures.
Manly Tears: Sheds them for the first time after Tripitaka forgives him and takes him back in (the first time), and with some surprising-regularity later on when he gains a sense of compassion.
Munchkin: In the first seven chapters all his actions are about gaining things for himself: the most powers, the best weapon, the best armor, the greatest title, etc.
Nigh Invulnerable: Even demonic weapons wield by powerful monsters bend and crack on his head after hitting him.
Not in This for Your Revolution: Monkey is only interested in joining the pilgrimage in the first place because it was join, or stay under the mountain for the rest of eternity. Afterwards, he comes along only in hopes of getting the Circlet of Headaches off his head. Eventually he comes to genuinely care about Tang Sangzang as a father figure that he loves and respects.
Number Two: The first disciple is the senior disciple which means he has authority over Pigsy and Sandy.
One-Man Army: In the first part of the story, Monkey takes on the entire military force of Heaven. He wins singlehandedly, although this is more of Conservation of Ninjutsu, because in a few other story arcs he has to seek help to deal with certain demons.
Rage Against the Heavens: Due to wounded ego and bruised pride more than anything; life on earth was pretty sweet for him, he just got so arrogant he thought he should be a god as well.
Restraining Bolt: To be able to control him, Tripitaka tricked Monkey into putting on a magical headband so that he could cause Monkey intense headaches whenever he got up to mischief.
Screw the Rules, I Have Connections!: Often uses his supernatural contacts to bail the group of trouble but just as often the trope is inverted: the person in question won't help the group because they know him.
Small Name, Big Ego: At first when he was a mere monkey king that called himself "Great Sage Equalling Heaven". Skip 500 years and his reputation has caught up with his ego and lesser gods voluntarily call him "Great Sage".
Smug Super: Monkey is incredibly powerful, and unbelievably full of himself as a result.
Telescoping Staff: His 'As-You-Will' cudgel is both the original and one of the most extreme examples. He likes to shrink it to the size of a needle and store it in his ear when he's not bashing people's brains in with it.
Despite being almost almighty on earth or air, he sucks at underwater battles, and is forced to rely on Pigsy and Sandy to fight against water-bound enemies.
The magical eyes he gains after being locked in Lao Zi's crucible make him vulnerable to smoke.
Weapon of Choice: Simple Staff, though Monkey's is by no means simple. Not only can it hit hard enough to take down gods, but it can extend to any length (from toothpick size to several hundred miles long) and provide Monkey a bridge to heaven.
Wouldn't Hit a Girl: While he does threaten and even fight female demons, he rarely kills them (except for Gold Horn and Silver Horn's mother), and during the Spider Women act he refuses to attack the seven unarmed demonesses, as such an act will dishonour him.
Chen Xuanzang/Tang Sanzang/Tripitaka
Adaptational Heroism: Popular adaptations, especially the 1996 and 2002 Hong Kong adaptations, portrayed him as a wise and merciful master and downplayed his naiveness and hypocrisy, a reversal from his original portrayal in the novel.
Celibate Hero: Despite women lining up to have sex with him he staunchly refuses because he's a monk.
The Chick: Honorary status as this because he's so feminine a character that a lot of live-action portrayals of the series have women playing the part.
Chick Magnet: Every female they encounter, whether human or demon, desires him. The only exception is Guan Ying.
Decoy Protagonist: Possibly the oldest extant example. His primary purpose is to be kidnapped every two minutes so Sun Wukong can get all Bad Ass while rescuing him.
Distressed Dude: He's not only a pacifist but completely untrained in magic or fighting.
The Face: He does all the talking with muggles etc because he is a courteous monk and his companions are scary-looking (and in Wukong and Wuneng's cases, very rude) demons.
This Looks Like a Job for Aquaman: He can sit perfectly still for up to three years and he's very proud of this fact. It only came in handy that one time the group was challenged to a meditation duel.
Incorruptible Pure Pureness: The reason why he was sent on the pilgrimage in the first place... but also the reason why he gets into so much trouble, as A: he's too "pure" to resist even the most obvious deceptions or traps, and B: his purity draws swarms of monsters that hope to consume that purity and increase their own power.
The Leader: He's supposed to be this (Charismatic type to be exact) but he spends too much time kidnapped to do any real leading. They rarely listen to him anyways.
The Load / The Millstone: Tripitaka not only constantly gets into trouble, he frequently diverts his disciples from their quest to pursue other minor goals, refuses to heed their advice, and places restrictions on their actions that make them harder pressed to go about their tasks. He also has absolutely no skills at all that let him contribute anything of worth when they get in trouble.
Stupid Good: Tripitaka takes "goodness" to levels of life-threatening stupidity on more than one occasion. His disciples call him on this often, but he never listens to them.
Supernaturally Delicious and Nutritious: Literally, as he's so infused with holy power that eating even a single bite of his flesh will extend a demon's lifespan. Female demons seem to find him sexually attractive as well.
Thou Shall Not Kill: Being a buddhist monk one of his vows is not killing anything ever. His companions think this is ridiculous.
Zhu Wuneng/Zhu Bajie/Pigsy
Adaptational Heroism: Kind of. The original Pigsy was originally a demon who eats humans just like Sandy did. Popular adaptations tend to omit this detail.
Attack of the 50-Foot Whatever: At one point, the group's path is blocked by a huge mountain of rotten fruit. His solution? Turning into a colossal pig and eating the way through the thing.
Big Eater / Gluttonous Pig: When the quest is over, the still-too-crude Pigsy is offered the existence as a lesser god; "Cleaner of the Heavenly Altar", which means eating all of the food that is offered to Buddha for the rest of time. He thinks this is the best job ever.
Butt Monkey: Other demons often think of making hams out of him, and Sun Wukong loves to prank him.
Casanova Wannabe: Pigsy really likes the ladies — in fact, he was thrown out of heaven for trying to make off with a celestial maiden — but his efforts at wooing them are poor to say the least.
Early-Bird Cameo: In the novel both he and Sha Wujing are met by Guanyin earlier and informed of Tripitaka.
Elemental Powers: He claims that his rake can summon flames when hold upward and gusts of wind when swung down. At one point he also turns himself in cold lightbeams to run away from Sun Wukong.
Not in This for Your Revolution: Pigsy just wants to go back to Heaven, he doesn't care about the scriptures at all. Being turned into something more attractive than his current humanoid pig-monster shape would also be nice. Like Monkey, he comes to genuinely care about Tripitaka as a surrogate father, maybe even moreso due to his immature nature.
Pig Man: This is part of his punishment; he was better looking back in Heaven.
Vitriolic Best Buds: With Monkey. They constantly give each other grief on the journey but are still fellow buddhists.
Worf Effect: When first introduced, Pigsy battles better against Monkey than many of the actual gods did during Monkey's war against heaven. Later on, he's usually swiftly beaten so that Monkey can then beat the creature who beat up Pigsy. In his defense, he can often fight several demons on equal ground, but they either run away or call for help.
The Atoner: Though all three disciples are nominally working for their atonement, Sandy seems to be the only one who actually cares about making himself a better person.
The Big Guy: Though often mistakenly portrayed as a Kappa, the original source material depicts Sandy as a kind of river-dwelling Oni. In either case, he's the tallest of the disciples, though he's much more the thoughtful type than the bruiser type.
Not in This for Your Revolution: Sandy just wants to be let back into heaven but just like his two elder "brothers", he comes to care for Tang Sangzang too, though more as a friend rather than a father-figure.
Out of Focus: Sandy is usually a secondary character in all the stories.
The Quiet One: Sandy rarely has much to say, but is often the most practical and philosophical of the group.
Out of Focus: Even the original author seems to forget he exists more often than not. Yu Lung's big character moment is when he first appears and eats Tripitaka's horse, then has to turn into a replacement horse. After that, he's in the background until they reach the end of the Journey and he can turn back into a dragon and fly off home. This turned out very badly for him. The Other Wiki calls him "the horse" or "the dragon prince", insists there are four main characters, and doesn't have a page on him. Ninja Sentai Kakuranger claims that there are four main characters, and that their fifth is a totally original creation. Most local theatre productions of the story leave him out entirely.
Team Pet: The role he's often relegated to; the horse.
Gods and Immortals
The Bodhisattva Guanyin
Team Mom: Always ready to advise or help Monkey when he's in pinch.
Animal Stereotypes: Averted. The one star who does lose himself enough to eat an enemy happens to be a moose spirit
Anthropomorphic Personification: Of the twenty-eight Chinese Lunar Mansions. They're a weird case, since their true forms are actually shape-shifting animals
Elemental Powers: Invoked. They're divided into the five Chinese elements plus sun and moon, with four stars to each element. The only group that specifically gets a reference to their elements are the Four Heavenly Wood Star Spirits.
I'm a Humanitarian: Since they're originally animal spirits, they will eat their opponents if they lose control of their instincts. One of the rhino demons was unfortunate enough to experience that.
I'm Melting: What happened to them. Luckily, their true forms were spared.
Overshadowed by Awesome: In most of the fiction depicting/nodding them, the Gourd, the Fan and the Sword are probably the most famed treasures in that order. The Pot and Rope? Good luck finding someone who knows what they do.
Too Dumb to Live: Leaves the fight against Sun Wukong after spitting some fire against him without checking out his health status. Later when he sees Guanyin's empty Lotus throne he smugly sits on it acting as her. It goes as well as you could possibly imagine.
X on a Stick: As if his fire powers weren't enough, he has a spear tipped with flames.
The Scorpion Lady
Affably Evil: Civil torwards Tripitaka but much less so towards the three disciples.
Dark Action Girl: She's more than capable of fighting the three heroes on equal footing.
Femme Fatale: Actively tries to force Tripitaka to sleep with her.
Poisonous Person: Her touch (technically the stinger), which she uses on Monkey and later Pigsy.
Prongs of Poseidon: Her weapon is described as a large trident-like spear. Apparently it was her pincers.
Animal Motifs: Lion, Elephant and Peng (a mythological giant bird).
Adaptational Wimp: Very much so in the 1998 Hong Kong TVB Adaptation. Their goals, motivations, and the general plot were completely altered. In the original novel, they are crafty villains seeking to eat Tang Sanzang, which Sun Wukong can't defeat by himself. In the 1998 Hong Kong TVB Adaptation, they are a comedic trio of cowardly incompetent jerkasses who merely seek power and wealth and are barely a match for Pigsy.
Hoist by His Own Petard: The Lion tries to swallow Monkey, who wreak havoc in his innards. Later the Elephant tries to seize him with his trunk, but he's defeated when monkey use the trunk to beat him up.