Note that the intended panel is the first one that's actually the "introduction" of the character, where you can imagine that a text like "introducing: Vegeta" would appear. For example, Nappa has a first panel with a close-up of him just saying "Raditz is dead". But his actual "here is the new character" panel is the one the next one where he's sitting with Vegeta eating aliens. So seeing the character's arm or from the back doesn't count as their actual introduction panel in this thread.
[spoiler]

Bacterian is introduced one panel later than other unknown contestants (Jackie Chun, Lanfan, Nam and Guilan are all introduced in the very same panel), as he triggers intense reactions from his surroundings.
Especially Goku, who can barely bear his presence due to his evolved sense of smell.[/spoiler]
BEERUS
[spoiler]

Beerus is introduced showing two things about him: he's very much about food, and he can be quite grumpy.[/spoiler]
BULMA
[spoiler]

Bulma is first introduced as a young girl who came in her own car, apparently looking for something in the jungle.
She has blue hair, but switches to purple hair after chapter 2, while retaining blue hair forever in the anime.[/spoiler]
CELL (1st form)
[spoiler]

The mysterious monster seen by God is finally revealed and looks unforgiving: a giant insect with no discernable expression on his face while his holding his latest victim after wiping out all other lives in the city. Much like Piccolo wondering if he can even speak, his insectoid appearance and lack of any form of expression will make the reader wonder if he's not an actual monster with no real conscience at first.
It is still without a word or without any facial expression that he will stab the poor man with his sting and make him melt from the inside to absorb him, confirming an intense horrific impression on the reader.[/spoiler]
CELL (2nd form)
[spoiler]

Cell's second form is revealed as seen slightly from above. Given his massive size in this form, it is probably a nice choice to fit him in the panel and insist on his much wider upper body. It could very well be what Ten Shin Han sees from where he is.[/spoiler]
CELL (Final form)
[spoiler]

Smaller and thiner than his second form, Cell can be seen from the front this time, which is reminiscent of Freezer's final form. He is put on the foreground, being superimposed to the actual panel and going beyond its borders. Colors also put an emphasis on Cell, with the background (including shocked C-16 and Krilin left in the background) having washed out colors.[/spoiler]
CHICHI
[spoiler]

Chichi first appear as a damsel in distress in a lethal situation! However, this first panel gives a false impression that is quickly put to rest, as the young girl quickly proves that, against expectations, she is the real danger for others here!![/spoiler]
FREEZER (2nd form)
[spoiler]

Freezer's 2nd form is very tall and first appears on a full page, with the monster looking huge that way when he's actually not even standing yet![/spoiler]
FREEZER (3rd form)
[spoiler]

With the wind blowing on the landscape and his monstrous new body that seems like he's preparing to grab the reader, this third form takes the nightmare one step further as the tyrant becomes more and more intimidating.[/spoiler]
FREEZER (Final form)
[spoiler]

With an empty landscape behind him, Freezer's final form is revealed when the dust and smoke dissipate. He has none of the monstrous smile of his previous forms, with a terribly cold look on his face aimed straight at the reader with a stare of death.
Although he should theoritically look less intimidating (as pointed out by Krilin), the reader feels quite the opposite: that simple form is way more frightening than any of his previous form, and this first appearance will undoubtedly send chills down many spines as it seems that all superfluous elements are gone and play time is over.[/spoiler]
GIANT APE (Son Goku)
[spoiler]

The Giant Ape form is first introduced with a double-page to emphasize the absolutely gigantic feel it conveys!
A turn of event that is surprising to say the least, to the point that even Toriyama plays along with the narration box: "Seeing the full moon, Goku turned into a monstrous giant ape!! The author himself is in shock!!! I didn't know! I didn't, I swear!"[/spoiler]
GOKU BLACK
[spoiler]

That new enemy is introduced in a fairly dramatic way, with his evil grin lit by the surrounding fire, all of this with the face of our hero himself promising Trunks that his time to die has come.[/spoiler]
GYUMAO
[spoiler]

Gyumao first appearance is quite agressive, immediately attacking Bulma and Oolong and being quite intimidating with his giant size and masked face. Like some giant ruthless butcher or something. Luckily, Goku quickly breaks the ice and reveals Gyumao's big soft heart, that will only soften more as he gets grandsons.[/spoiler]
HIT / CABBE / MAGETTA / FROST / BOTAMO
[spoiler]

The first introduction of the warriors from Universe 6. Since Frost is the one having the attention of our friends (and likely the reader) - especially given the recent fight against Golden Freezer -, he is the one placed on the foreground.
But Hit is also at the center of his team.[/spoiler]
JACKIE CHUN / LANFAN / NAM / GUILAN
[spoiler]

Although he's a very important character at this event, Jackie Chun is introduced without much emphasis on him and treated like all other contestants also introduced here (except Bacterian, who has his own introduction panel as his arrival triggers a specific reaction). However, he is the only unknown contestant (at this point) to have a line in this introduction panel shared by all "new" contestants aside from Goku, Krilin and Yamcha.
Yamcha says "Oh! So you could go and see everyone?" to which Goku replies "Oh yeah! That was awesome!".
As for Jackie Chun, he is talking to Lanfan: "Ho ho ho... I take it you've been selected too, miss?"
Other contestants may or may not show what they're about: Nam is already shown as a serious priest-type warrior, while Lanfan's girlie technics are not revealed as she just seems like a regular girl relaxing, and Guilan has a normal stance, going along with the feel of a typical monster-type warrior.[/spoiler]
KAME SENNIN
[spoiler]

Kame Sennin makes an unusual entrance, arriving on the back of his turtle, who promised Goku and Bulma to come back with a reward.
While the turtle says "Sorry I kept you waiting !!", Kamé Sennin says "Hello!" in English.[/spoiler]
KRILIN
[spoiler]

Krilin is first introduced as a self-confident, independant boy. Arriving on his own on Kame Sennin's island with a proud grin on his face, he might not seem likable at first and will give the innocent Goku a hard time. But it is soon revealed that this is a deceiving first impression as Krilin was bullied, can easily get scared, but is also very friendly, quickly becoming Goku's best pal for the rest of his life.[/spoiler]
LUNCH
[spoiler]


Lunch is first introduced in her furious form, clearly shown as having trouble with the police, while also being a badass able to sustain a chase.
A few panels later, her real, calm form is introduced as quite the opposite: looking innocent and lost, out of her broken motorcycle.[/spoiler]
MAI
[spoiler]

Mai is introduced as what seems to be a badass and serious opponent, when efficiently stealing the Dragon Balls from our heroes with Shu's help.
It is soon revealed that there is more comedy to this character than meets the eye, much like for the whole Pilaf gang.[/spoiler]
OOLONG
[spoiler]


Oolong first appears when stories about him are being told to Goku and Bulma. He has a demon form. The man explains: "Actually, Oolong came here just yesterday, with the shape of a demon. And he took notice of... my daughter..." while Oolong states: "Wa ha ha! I like this girl!! I'm gonna make her my wife!! I'll come get her tomorrow at noon, so make her stuff ready!!"
But Oolong's real appearance is revealed later, when he barely escapes Son Goku after noticing his transformation time was coming to an end. He hides just in time for the transformation to end, sighing in relief.[/spoiler]
PILAF
[spoiler]

Pilaf is first shown with the two agressors of our heroes apologizing to their boss, instantly placing him as the mastermind behind the theft of the Dragon Balls.
He says: "It would have been wise to check the number." to which Mai concedes "Yes, it's unforgivable." and Shu states "I thought there were all of them...".
A translation note explains how Pilaf wears the two kanji forming the word "chahan", related to pilaf rice.[/spoiler]
PUERH
[spoiler]

Puerh is first shown spying on Goku and the others before warning Yamcha of their presence.[/spoiler]
SHENRON
[spoiler]

Shenron is revealed way before his actual appearance in the story, when Bulma talks about him to Son Goku.
Bulma explains: "When you gather the seven Dragon Balls and say the magic formula... Shenron, God of the dragons, appears to grant you any wish you want!!".
A translation note explains how naming him "Shenlong" would be illogical, since the Japanese transcription is more coherent with other names also choosing the Japanese transcription as opposed to the Chinese pronounciation (a choice also made for the Dragon Balls with "Su Shinchu" instead of "Si Xing Qiu", with the explanation being that it's simple that way - also it is not stated, it could be because it fits what people hear in the Japanese anime dub as well).[/spoiler]
SHU
[spoiler]

Shu is first introduced while inside a robot to steal the Dragon Balls from his friends. He seems serious in his mission, much like Mai at the beginning.[/spoiler]
TO THE CARROTRANSFORMER
[spoiler]When his men are in trouble against Son Goku, they call their boss, who just silently steps out of his car to reveal himself.
[/spoiler]SON GOKU
[spoiler]


Son Goku's introduction panel is debatable: the very first panel of the whole story does the job, but looking at the second panel, it also looks like the actual introduction panel. Since both panels work as introduction panels for him, I'm showing both.
The first one immediately introduces him as the boy from the jungle, pretty comfy with his wild surrounding. He says "Oh, hi there!" to the monkeys while the narrations initiates the story: "This story takes place thousands of miles away from any city, way deep into the mountains. This is where a strange yet wonderful adventure begins..."
The second one introduces Goku's apparent martial arts skills and his traditional-looking, small house.[/spoiler]
SUPER SAIYAN
[spoiler]

The introduction of the Super Saiyan form, with an intimidating look in Goku's eyes going straight at the reader as if he was in Freezer's place. And you don't want to be in Freezer's place at this moment.[/spoiler]
SUPER SAIYAN 2
[spoiler]

The first appearance of a new form later called "Super Saiyan 2", filling the whole panel with electricity, rocks flying, dust flying, and an incredibly intense aura.[/spoiler]
SUPER SAIYAN 3
[spoiler]

The introduction of Super Saiyan 3, unleashing a tremendous burst of energy filled with noisy electricity and pushing clouds themselves away for the warrior to be surrounded by the bright blue sky.[/spoiler]
SUPER SAIYAN GOD
[spoiler]

The Super Saiyan God, unlike previous forms, appears as a close-up as opposed to a view on the full body.
This is likely due to this part of the manga being drawn by Toyotaro instead of Toriyama. It could be to insist on Goku's different facial traits (more youthful and relaxed) with this new form.[/spoiler]
THE TURTLE
[spoiler]

While Goku is training crushing rocks with his arms, he suddenly and unexpectedly lifts Kamé Sennin's turtle.
This is when the turtle is revealed too, so that the reader is as surprised as Goku himself.[/spoiler]
YAMCHA
[spoiler]

Yamcha's presentation panel comes only at the very end of the chapter, with a lot of minor panels depicting him observing Goku and his friends in the desert and deciding to attack them.
The text reads: "All of a sudden, Yamcha and Puerh, thieves of the desert, enter the stage!! An upcoming fight is inevitable!!"[/spoiler]




[/spoiler]