This is the dragon of the Earth's dragonballs which were created by Kame when he had all his power. You must collect 7 dragonballs to summon Shenlong and you get only 1 wish. Shenlong does not have the power to bring someone back to life more than once, or kill someone who is stronger than him. When Kame fuses with Piccolo the dragonballs disapear. Dende makes a new dragon that is the same as the old one however can now grant 2 wishes and has the power to bring a group of people back more than once as long as they died by the same person.
This is the dragon of the Planet Namek's dragonballs. They were created by Guru. You must collect 7 dragonballs to summon Porunga just like the Earth's dragon however Namek's dragonballs are much larger than Earth's. Porunga has far more power than Shenlong and he can bring people back to life an infinate number of times. Guru passes the power of these balls onto Dende after he dies.
Ii - evil dragon of the 1 star dragonball; strongest of the evil
Shenlongs. It fused with all the dragonballs
Ryan - evil dragon of the 2 star dragonball. This dragon of water
(pollution) was born when Bra was wished back to life
San - Suu's older brother; evil dragon of the 3 star
dragonball. This dragon is associated with ice.
Suu - evil dragon of the 4 star dragonball. This dragon of the sun
(heat) was born when Daimao wished to restore to full power.
Uu - 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
Ryuu - evil dragon of the 6 star dragonball. This dragon of hurricane
was born when Oolong wished for a pair of panties.
Chii - evil dragon of the 7 star dragonball. This dragon with the
ability to absorb and control other creatures was born when Bulma revived
the people killed by Majin-Vegeta