Vegeta

"I am Vegeta! Prince of all Saiyans!"

- Vegeta

"Saiya-jins have their power levels examined right after they are born. The scum that have lower ratings, such as yourself, are sent off to planets that do not have terribly formidable opponents. In other words... You were a left-behind!"

- Vegeta, based on the manga before fighting Goku

"Nobody destroys Kakarot while I’m around. Destiny has reserved that luxury for me!"

- Vegeta

"It's over NINE-THOUSAND!!!"

- Vegeta, about Goku's power level (and the start of a meme)

"Goddammit, Nappa!"

- Vegeta (TFS)

Vegeta is an antihero from the Dragon Ball Franchise and Dragon Ball Z Kai series. He is one of the last surviving members of a race known as the Saiyans, who were destroyed when Frieza blew up their planet. He joins Goku in his fight against Frieza, and is killed. Vegeta was brought back to life by the dragonballs, and from then on, is a reluctant member of Goku's team. He switches sides often throughout the series, whether it be mind control or him being power mad, in the end he always fights Goku. Though eventually, even he cannot keep up with Goku. Vegeta made his first appearance in Dragonball Z.

The Saiyan Saga
Vegeta first appeared in the Saiyan saga of Dragon Ball Z. Vegeta is the prince of all Saiyans, and after having their planet destroyed Raditz goes to earth to find his younger brother Goku. After they fight him Piccolo tells Raditz about the dragon balls, and how if you collect them all you receive a wish. This statement was transmitted to Vegeta and Nappa who start on their way to Earth. Vegeta wants to wish for immortality with the Dragon Balls. However, it takes them a year to reach the planet Earth, giving Goku and company time to train. When they arrive, Goku is still dead from the battle with Raditz, so Piccolo, Krillin, Tien, Chiaotzu, and Yamcha have to hold the two Saiyans off. At first Vegeta creates Saibamen, green plant fighters that had the same power level as Raditz. One of them kills Yamcha, while the others are defeated. Nappa then starts fighting, and despite all their training, Nappa is stronger than all of them, and manages to cut off one of Tien's hands. Chaiotzu blows himself up on Nappa's back hoping to kill him, but it doesn't work. Vegeta sits back watching all of this, and Nappa targets Gohan. Vegeta offers the Z fighters three hours for Goku to show up, and three hours later, after Goku not showing up, they continue their attack. Nappa sent a blast, and Gohan, paralyzed by fear, is saved when Piccolo jumps in front of the blast. Goku shortly arrives, and makes quick work of Nappa. Then Goku confronts Vegeta in a showdown.

Vegeta then starts a one on one with Goku in a wasteland, so Goku could avoid any unnecessary casualties. Vegeta then tried to finish Goku off with his Galick Gun, but Goku sent a Kamehameha wave to hold off the Galick Gun. After Vegeta is outclassed by Goku, he turns into a Great Ape (via power ball). Goku attempted to use the Spirit Bomb technique on Vegeta that King Kai had taught him, but was caught off guard by Vegeta's blast attack when he recovered his sight from the Solar Flare. Goku used up the last of his energy and shot Vegeta in his right eye, blinding it. Then Vegeta started to crush the weakened and injured Goku until Gohan and Krillin came to the rescue. Then suddenly, Yajirobe appeared out of nowhere and cuts off Vegeta's tail, saving Goku and turning Vegeta back to normal. The evil Saiyan then got angry and attacked Gohan. Goku then gave Krillin the Spirit Bomb energy and fired it at Vegeta, but after that, Vegeta went into a rage and badly injured Gohan. Then Gohan looks at the power ball and turns into a Great Ape. Vegeta blasts Gohan's tail and Gohan starts to turn back to normal, then he falls on Vegeta, defeating him. With Vegeta seriously injured, he is forced to retreat but Krillin is close by and he is about to kill Vegeta when Goku stops him. Vegeta then vows he will kill them all and leaves in his space pod.

The Android Saga
In the Android Saga, Vegeta and his son Trunks train to fight two androids, 17, and 18, and become the first "ascended" Saiyans in the series. A form in which a persons strength massively increases, but their speed decreases. Vegeta became powerful enough to defeat Cell, who had absorbed android 17, but Vegeta touched on his pride, and against Trunks' wishes he helps Cell get android 18 and obtain his perfect form. Once Cell reaches this form however, Vegeta realizes he is out matched and stops fighting him.

The Fusion Saga
With the sorcerer Babidi about, and with his ability to unlock the anger in people's hearts, Vegeta let's himself fall victim to him, missing the feeling that he used to have when all that mattered to him was himself, and hoping to defeat Goku. So, he becomes Majin Vegeta. He confronts Goku (Against Babidi's wishes) and they fight. In the end, Goku is still able to defeat him, and Vegeta self-destructs himself in hopes of destroying Buu. This, however, does not work and Fortuneteller Baba takes Vegeta back to the world of the living to help in the final battle. He was eventually wished back along with the others who died during the Buu arc (except for the evil ones like Babidi).

Dragon Ball GT
Baby took control of his body to become Baby Vegeta.

Attack of the Saiyans
Vegeta as well as Nappa where the main villains with Vegeta being the final boss

Trivia

 * When Vegeta says the iconic one liner of "it's over NINE THOUSAND", it was actually a translation error that was corrected in Dragon Ball Kai where he instead says "it's over EIGHT THOUSAND."
 * Vegeta is very much like Sun Wukong from Journey to the West, in that he gladly fights alone against superior numbers, filled with pride and the belief that he is stronger than the gods, more powerful than the “Will of Heaven” and even the Buddha. Sun Wukong is the character Son Goku is named after, but Vegeta inherited his cocky attitude.