Dragon Balls (Darknesslover5000)

Dragon Balls are the namesake artifact of the Dragon Ball series. They are orange, crystalline spheres with the ability to call forth a colossal dragon which has the ability to grant wishes to anyone who gathers all seven of them.

Description
Dragon Balls come in sets of seven with each ball containing the number of stars that signifies its respective number in the set. Dragon Balls are difficult to find because they are scattered all over their respective planet (Earth and a few other planets which have their own set), and are deactivated for a year after every wish, disguising themselves as stones. To have the opportunity to summon a Dragon, one must travel all over the globe to retrieve them. As technology progressed, this became somewhat easier, and became relatively simple with Bulma's invention of the Dragon Radar.

Restrictions on the Dragons powers are set by the relative capabilities of the Dragon Ball set's creator. A big problem throughout the series is that with any set of Dragon Balls is that their creator must be alive for them to function, otherwise they will be stones for eternity. This often results in the Z Fighters protecting their creator with their lives.

Since all seven Dragon Balls must be brought together (though it is unknown exactly what the maximum distance between the balls for them to be considered together is), it is often a sound strategy employed by the villains of the series to find one Dragon Ball and hold on to it, while the Z Fighters go through the trouble of finding the other six, after which the villain will step in and steal them. Since this strategy technically works, but is considered cheap, the Z-fighters do not usually employ it, as they prefer to fight fair.

Earth and Namekian Dragon Balls
The Earth Dragon Balls are about 7.5 cm (approximately 3 in) in diameter, and they summon a dragon named Shenron. They were created by Kami, and later re-created by Dende. Shenron can grant a wish within its powers as long as it does not kill, create love, repeat a wish he previously granted, and a few more restrictions. Legitimate wishes include eternal youth, immortality, bringing back a scorched forest or even an annihilated planet. Also, it is possible to return a person to life, although only if they meet certain criteria, like dying of unnatural causes (like murder for example) or (if more than one person) within a year before, and each individual can only be brought back once. The Eternal Dragon will grant the first wish uttered after it was called, by whomever is present. The Earth's Dragon Balls are later revealed to "reset" every 100 years, allowing wishes that have been granted before to be granted again.

Unlike the Dragon Balls of Earth, the approximately basketball-sized Dragon Balls of planet Namek summon a different dragon, Porunga and can grant three wishes, due to their creation by Grand Elder Guru. Since the years on Namek are shorter (130 Earth days), they can also be used more frequently. However, Porunga is only capable of one individual's revival, whereas the Eternal Dragon of Earth can wish many, even an entire planet's population (if you can state your will in one wish). Additionally, the Namek Dragon Balls require the summoner to say a password before the dragon can be summoned (the password is Porunga), and the wish must be spoken in the Namekian language (the Z Fighters used Dende to translate their wishes).

Of course, one notable advantage that the Namekian dragon balls have over that of Earth is that they can revive a person as many times as wished to (something that even Dende's upgraded Shenron could not do). Sometime after settling on New Namek, the Namekian's decided to modify their existing Dragon Balls, giving Porunga the ability to bring back to life as many people as needed (this was done as a reaction to their experiences dealing with Frieza).

The Namekian Dragon Balls are a unique exception to the link between their creator and their existence, since Guru, at the end of the Frieza Saga was able to name Moori as the new Elder right before he died, after which the Dragon Balls' existence rested on the new Elder's fate. It is unknown if the Earth's Dragon Balls can be passed on in such a manner. In the Kid Buu Saga, Elder Moori revealed that he had restyled the Namekian Dragon Balls giving Porunga the ability to grant the wish of resurrecting an entire populace not just individually. It was also revealed that Porunga could in fact grant a wish that is not spoken in Namekian language as Dende asked for the wish of all those killed by Buu in normal language. Like Earth's Dragon Balls, the Namekian Dragon Balls can "reset" though they reset once every 50 Earth years.

The Legend of Earth's Dragon Balls
Master Roshi gave an explanation on the "origin" of the Dragon Balls. However, this explanation is only present in the anime, and it is completely contradictory with the explanation given later in the series, about Kami being their creator. However, Roshi's tale is only something he had heard, so it was probably a legend with no real basis.

''"The Legend, as I was told, goes something like this. In the beginning there was only one Dragon Ball. It was huge. I mean REALLY huge, it had to be. It held all of the mystical energies of the universe. An ancient tribe discovered it, and was inspired by it's magnificent power. They built a shrine around it, and protected the orb by placing it in the mouth of a giant Dragon statue, said to be it's eternal guardian. You should have seen the detail on this thing, it was INCREDIBLE, scales made of Ruby, teeth of pearl -speaking of pearl, they say there was this one native girl ("GET ON WITH IT!")- yes, well, the tribe enjoyed years of prosperity until one day, evil paid a visit to the village in the form of a band of thieves. These agents of Darkness stormed the temple in an attempt to steal the Dragon Ball for their own selfish gain. They were shocked to discover the true power of the Ball. To ensure such an attack never happened again, the Dragon Ball was divided into seven smaller orbs, and scattered across the globe. Separately, the Dragon Balls were useless, but when all seven were united, then a single voice could summon the Eternal Dragon for one wish, and one wish only. Some wishes were pure. but others were tainted by blind ambition. This led to pain and suffering as an unjust few wished for power and dominion over mankind. But as the story goes there will one day come a hero who will use the Dragon Balls for goodness, and bring peace and unity to the world once more."''