Shenlong is a magical dragon that is part of the Dragon Ball anime TV series, created by Akira Toriyama. The name Shenlong means “God Dragon”.

The Dragon Balls are a component of the universe. They are seven magical spheres that are dispersed through world. When they are gathered, they can be used to summon Shenlong. He can grant a wish, within certain limits. After granting the wish, the spheres disperse again all over the Earth and they stay inert during a year, with no possibility of summoning Shenlong during that time.

At the beginning of the series, it was very difficult to collect all seven spheres; but after Bulma – a creative genius girl – invents a dragon radar, which detected the dragon spheres, the task of finding them was very easy.

As mentioned, Shelong can grant any desire while it does not exceed certain proportions and limits. It cannot make someone to fall in love, or to resurrect someone that has died many yeayrs ago. It also cannot change the results of historical events.

The power of the dragon balls grew, later in the series. Thanks to Dende, the new keeper of the Dragon Balls, they could grant up to two wishes per year.

In Dragonball GT, a evil Shenlong appears as Black Star DragonBall. This character was borned when the dragon spheres were corrupted. All the dragon balls were transformed into individual dragons that fought Goku and friends.
NAMEKIAN DRAGON

Porunga is the eternal dragon invoked at Namek when all the namekian dragon balls are gathered. Porunga has a much more frightful appearance than the Earth Dragon, Shenlong. This namekian dragon can grant up to three wishes, but the caster must speak Namekian in order to have his wishes granted.

Initially, Porunga had the capacity to resurrect only one person. Later, his energy grows and gains the power to resurrect many people at the same time. This feat is seen when planet Earth was destroyed (twice n the series), and Porunga brought all the people back to life.