Son Goku

Son Goku is the primary hero of the Dragon Ball series. The series started out with Goku as
a child of age 12. Once he grew up and his son was born, the TV series' name changed from
Dragonball to Dragonball Z. At the end of the series, Goku was roughly 45 years old.

Goku is a Saiyajin whose native world is the planet Vegita. He was sent to Earth in a space
capsule right after he was born so he could conquer the planet. However, he hit his head and
lost his "programming," thus becoming the kinder, gentler Goku we see in the series. Goku
was raised as a human on Earth, and did not learn of his true nature until his brother Radits
came to Earth...

Later, when Goku's rage was awakened by witnessing the death of his friend Kulilin, his
Super Saiyajin power was awakened. When he goes Super-Saiyajin his eyes turn green and
his hair gold. Currently, Goku can go to the 3rd stage of Super-Saiyajin power.

Son Gohan

Son Gohan is Goku's first son. At the end of the series he was 26 years old . For a short while after the second time Goku died in the series, Gohan became the
primary character. Gohan is the most powerful non-fused character in the DBZ world, but
lacks the love of fighting his father has and thus rarely uses his full strength.

Gohan is a very good-natured boy and unlike his father, hates fighting, although for a while he
was more powerful. He is very polite towards just about everyone except to his enemies,
and when he's pissed off. Gohan is very bright and studies very hard, although this is
somewhat due to the wishes of his very strict mother...

Gohan is the first character in the series to have gone Super Saiyajin-2, during the Cell
Game; the power of his anger was kindled by watching his friends get beaten up, and the
death of Artificial Human #16 sent him over the edge. It was roughly at this time that the
series switched main characters from Goku to Gohan.

Piccolo

Piccolo is Goku's old rival. He was born after Goku killed his father when he was a kid; in
his last breath the old Piccolo spat out an egg, and the new Piccolo hatched. Piccolo then
went on to fight Goku in the final round of the Tenkaichi-Budokai, which he subsequently lost
by a very close margin.

Piccolo is a native of the planet Nameck, although he doesn't learn this for quite some time
after his first appearance. As a Nameck, he can regenerate almost any part of his body lost.
(usually the arms) He can also extend the range of his arms till they're really long. Later, he
goes to Nameck to help Kulilin, Goku, Gohan, and Vegita fight Freezer.

After the Tenkaichi-Budokai, Piccolo becomes more and more of a "good guy." Eventually
he becomes Goku's friend; fairly recently he got pissed off at Trunks and Goten for calling
Goku weak. Once one of the most powerful characters in the series, he has sort of reached a
"middle ground," neither weak nor strong among the Z fighters.

Vegita

Vegita is the "bad guy among the good guys." He first made his appearance back when
Gohan was 4. Although he fights alongside the other Z fighters, he is still decidedly evil. As
the prince of the Saiyajins, he is very proud, has a huge ego, and is constantly trying to prove
that he is the best fighter in the universe.

Vegita has a continual rivalry with Goku, or "Kakarott," (Goku's Saiyajin name) and is
obsessed with beating him in combat just to show that he is the stronger. This obsession with
trying to be stronger than Goku proves to be a fairly large weakness as well.

Despites his efforts to show otherwise, Vegita has changed and has developed a conscience,
and deep down cares about his friends. Furthermore, he is also somewhat emotional at heart.
He demonstrates this when dealing with his son Trunks, most notably just before he died
trying to kill Majin-Buu. Although he pretends to hate Goku with a passion in reality he
respects his power and maybe even likes him a bit.

Trunks

Trunks is Vegita's son. In his future, all of the Z fighters were killed by the Artificial Humans,
except for Goku, who died of heart disease. Trunks travels 20 years back in time to give
medicine to Goku so he can survive this disease and defeat the Artificial Humans. Trunks'
returning in time alters the past in other ways which can be seen later.

After giving the medicine to Goku, Trunks goes back to his own time, but returns again three
years later to help the Z fighters battle the Artificial humans. During this time, he becomes
extremely powerful and surpasses every other one of the Z fighters except for Gohan and
(maybe) Goku.

The Trunks here, "Future Trunks" and the "current Trunks" are radically different characters.
"Future Trunks" is very polite like Gohan and has very strong values, but the current "Chibi
Trunks" has a bad attitude and is somewhat like his father. Chibi Trunks never truly reaches
the power level of his future counterpart; possibly because he lived through mostly peaceful
times, whereas Future Trunks did not.