Dragons

The legend tells that when all 7 Dragonballs are united and the magic words are said, a mystical Dragon will appear, granting any wish asked.

 
When the Dragonball series started we only knew of the existence of a dragon (Shenlong), a sacred dragon created by God, able to grant any wish, but as the series unfolds we find out that not everything been said was correct. There are in fact two dragons:
 

  ShenLong - This being the Earth Dragon God, was created by Piccolo's good half (Kami Sama - God). Piccolo came from the Namek family who conceived the original Dragon (Porunga), so, when he came to Earth as a child (due to terrible weather problems in Namek, Piccolo was sent by his parents), he had the urge to create a similar dragon (he did not do this consciously, for he had no memory of his planet). In the beginning of dragonball we are told that once, a long time ago, there was no Dragonballs, you just needed to ask your wish to the Dragon, who would sit at a palace, but due to Man's greed and violence, God decided to conceive a way that only the most worthy could have their wishes granted, so he created the Dragonballs, which would be dispersed all around the Globe, making it difficult to gather all of them (especially without a Dragonball Radar, which was first constructed by Bulma). Shenlong, appears, when all the Dragonballs are united and the words "Ide yo, Doragon!" (Come out Dragon) are said, after a big "light show" the dragon comes out and grants the first wish asked of him (no matter, who says it). Though, being said in the beginning of the series that all your wishes could be fulfilled, the Dragon one limitation (besides only giving one wish!) he can't grant the same wish twice; this is a bit of a problem (especially in the second series), as deaths are common among the heroes, and nobody could be revived. Despite of some stranger requests (like the first time the dragonballs were gathered, where Oolong asked for some panties), in general, the more frequent requests are Immortality (normally the request of villains) and bring back people to life. The power of the dragon relies on the power of it's creator (this seems a bit of a problem, because if so, why can't Piccolo bring back people to life ? - the Dragon seems to be a parallel manifestation of his own power; example: a man can create a Formula 1 car, but he, himself cannot run at 300Km/h ) and if the creator dies the dragon dies too (making the death of Piccolo a problem). During the Cell Saga, Piccolo and Kami Sama finally fuse (this being a Namek only fuse) in order to fight Cell; so a new God is needed, and Dende is the chosen one; after some time in the job he decides to give the Dragon a power up, making him able to grant 3 wishes.
 

  Porunga- The Original Dragon, created by Saichouro (after Saichouro died, of natural causes, the role of "dragon keeper" was given to Muri - a Namek elder). Porunga is quite different from ShenLong, being also a lot bigger, his first appearance was due to the death of Shenlong (SonGokuu's friends and Piccolo fought Nappa and Vejiita. During that fight Piccolo was killed while trying to save Gohan's life - with Piccolo dead Shenlong ceases to exist), after the fight against Vejiita there was the need to revive their friends, so they left to Namek. To call this Dragon instead of "Id yo Doragon" (calling the dragon in Japanese), you have to say :"Takkarato Popporunga Pupirittoparo" (which in case you didn't notice isn't Japanese but Namekian). This dragon has the special characteristic of granting three wishes and is also able to grant the same wish more than once; though this the Dragon has a major handicap, he can't bring a large number of people back to life. At the end of Dragonball Z (or simply Dragonball in the manga), Porunga was given a power up, making him able of reviving a large number of people.

1 Star Dragon

Li-Shenlong

evil dragon of the 1 star dragonball. Ii-Shenlong  fused with all the dragonballs and became the strongest of the evil Shenlongs. (killed by Gokou)

2 Star Dragon

Ryan-Shenlong

evil dragon of the 2 star dragonball. This dragon of water (pollution) was born when Bora was wished back to life. (killed by Gokou)

3 Star Dragon

San-Shenlong

Suu-Shelong's older brother; evil dragon of the 3 star dragonball. This dragon is associated with ice.

4 Star Dragon

Suu-Shenlong

evil dragon of the 4 star dragonball. This dragon of the sun (heat) was born when Daimao wished to restore to full power.

5 Star Dragon

Uu-Shenlong

evil dragon of the 5 star dragonball. This dragon of electricity was born when Gokou was wished back to life to fight Nappa and Vegeta. (killed by Gokou)

6 Star Dragon

Ryuu-Shenlong

evil dragon of the 6 star dragonball. This dragon of hurricane was born when Oolong wished for a pair of panties. (killed by Gokou)

7 Star Dragon

Chii-Shenlong

evil dragon of the 7 star dragonball. Specialty: ability to absorb and control other creatures. It was born when Bulma used the dragonballs to revive the people killed by Majin-Vegeta. (killed by Gokou)