The story in short
Earth's greatest warrior Goku found out he is not a human but part of a warrior race called the Saiyans. Goku and his many friends that he makes along his adventures help save the Earth and the universe numerous times due to their tenacity to not allow evil to have its way. The Series is made of of 3 main parts, DragonBall, DragonBall Z, and DragonBall GT. There are multiple sagas in each part of the series which shows the growth of the "Z-Fighters" and the Main hero of the show, Goku.
Son of Bardock, Goku is the main and most loved character in the Dragon Ball saga. He is in every saga and nearly always plays an important role in the main villain's destruction. He first appears as Bulma is looking for the Dragon Balls and meets him because he had one of them. He then goes on a quest with her to find the other Dragon Balls. This is the first part of Goku's life. He will grow up and marry Chi Chi and have Gohan and Goten with her. He will then fight the invading Saiyans and destroy Frieza on Planet Namek by becoming a Super Saiyan, destroying the whole planet at the same time. Then comes the Android's saga in which he will fall in a dangerous state of a mysterious sickness. Trunks of the future will come and give him a medicine that isn't available in the present. Goku saved, he will later on fight Cell and sacrifice himself trying to destroy him. He will fail however but will help Gohan with his soul to finish off Cell. In the Buu saga, he will teach the kids Trunks and Goten how to fuse and later on fuse himself with Vegeta to become the powerful Vegito but will destroy Buu later on with the help of all the planet's vital forces. He will become a kid once again in Dragon Ball GT and go look for the Dragon Balls once again. He mastered all the forms of Super Saiyan through his adventures.
Gohan is the son of Goku and Chi Chi named after the man who found Goku and raised him from a young age. Gohan is first met in the first episode of Dragon Ball Z as a young and nervous child. Over the course of the series he grows and matures to become one of the strongest fighters in the universe. He has shown to have a secret power when he gets angry as evidenced in the Saiyan and Frieza Saga. He is the only known Saiyan to have a form much stronger than Saiyan that had to be unlocked by the Supreme Kai. At the end of Dragon Ball Z, he has a daughter named Pan who accompanies Goku in Dragon Ball GT.
Goten is the second son of Goku, and is a child in every appearance throughout the series until GT where he is seen as a teenager and shows that he has neglected training like his father and brother did in their younger years. Goten doesn't meet Goku until he comes back for the world tournament before the Buu Saga. Goten is trained by his older brother Gohan, and he mispronounces the Kamehameha attack calling it the KameKameha attack. He fuses with Trunks to form Gotenks.
Vegeta is the prince of the Saiyans, and the son of King Vegeta. Vegeta served Frieza as a child and eventually broke away after fighting with Goku and refusing to be the second strongest saiyan in the universe. He tries to kill Frieza after training and getting stronger believing that he had reached the form of Super Saiyan, (but failed) after helping Gohan, Goku, and Krillin kill his minions. After the Frieza Saga he became one of the "Z-Fighters" and is a hero for the rest of the series except when he gets possessed by Babidi in the Buu saga due to the fact that the Majin curse set upon him helps bring out the true nature of ones being which rekindles the thought that he should be the strongest in the universe and not Goku. He later returns to being a hero later in the Buu saga.
Trunks is the son of Vegeta. He is first introduced after the Frieza saga as a teenager who helps save Earth from the rebuilt Frieza and his father who try to get revenge on Goku while he is still traveling home. His main purpose was to return to help save his future from its current course and give Goku an antidote that is to save him from a heart disease that has yet to be discovered. He is later reintroduced as a baby and then as his young child self where he and Goten help fight Buu and use the fusion technique to form the Z-Fighter Gotenks. He is last Seen as a teenager in GT where he, Goku and Pan finish off the now legendary series while searching for the 7 dragon balls spread out across the Universe to save the earth yet again from imminent destruction.
Piccolo is a Namekian and is the final son of the evil King Piccolo. Piccolo was born only to avenge his father's death by defeating Goku but ending up becoming one of his greatest friends, and Piccolo was the second member of the "Z-Fighters." Piccolo has a very distinct appearance: he is green, pointy ears, always is seen wearing his purple training clothes and/or his white cape. Piccolo also has the power to recuperate from any wound or injury he has as long as his head has not been damaged. Piccolo starts out as being very cocky just like Vegeta but after his fusions with Nail and Kami all traces of evil are gone and Piccolo is born again as a pure soul. Piccolo becomes one of the most honorable and noble fighters in all of the series.
Before Dragon Ball Z Yamcha was a desert bandit, and an enemy of Goku just like Piccolo. Yamcha was the first to meet and make an alliance with Goku and from the fabled Z-Fighters. His major love interest was Bulma and was even her boyfriend for awhile. Yamcha's only fear is talking to women since he is a battle-hardened sand pirate. Yamcha dies a lot but always tries to fight the enemies invading Earth. He was one of the strongest fighters in Dragon Ball but not so much in Dragon Ball Z
Tien is a human with three eyes. Tien started out as a cold-heated, ruthless warrior. He fought Goku many times during Dragon Ball in the World Martial Arts Tournaments. In Dragon Ball Z Tien is training to surpass Goku's strength. Tien holds his own against the Saibamen but when put against Nappa he has his arm pulled off in a single hit. Tien spends a lot of his time in the after life with Yamcha training on King Kai's world. Unlike Yamcha who is obsessed with women, Tien turned down a date in order to continue his training.
Vegito is the Potara Fusion between Goku and Vegeta used to defeat Super Buu. Vegito's personality is a mix of Vegeta's cockiness and Goku's cheerfulness, the result is an immensely powerful warrior that ends up toying with his enemies. Vegito is about the height of Goku but his hair resembles Vegeta's more than Goku's.
Gogeta is the fusion of Goku and Vegeta by the Fusion Dance. Gogeta is often regarded to be the strongest warrior in the Dragon Ball Z Universe, even stronger than his Portara Fusion counterpart Vegito. Gogeta is very quick and powerful. Gogeta was able to power all the way up to Super Saiyan 4. In his super Saiyan state he was very calm and efficient, but like Vegito, in his Super Sayian 4 form he was very cocky and would toy with his enemies. Vegito also has a great combat tactical mind.
Videl is that daughter of Mr. Satan and the girlfriend (future wife) of Gohan. Videl goes to the same high school as Gohan. She finds out that Gohan is The Great Saiyan Man and agrees to keep his secret as long as he teaches her how to fly and enters himself in the up coming World Tournament. Videl and Gohan end up getting married and being the parents of Pan, who is one of the main characters in the Dragon Ball GT series.
Krillin is Goku's best friend. He trained with Goku as a child under the tutelage of Master Roshi. He is one of 2 characters in the series without noses (His daughter marron has no nose until she is a teenager). He is only seen bald until he and android 18 get married which he is then seen with a full head of hair. Krillin is in almost every fight, whether he is of use or not. He has died many times but has been brought back by different means, mainly by the dragon balls.
Gotenks is the fusion of Goten and Trunks via the Fusion Dance. This character first appears in the Super Buu Saga and the only purpose of fusing to make Gotenks was to defeat Super Buu. Gotenks is incredibly powerful, powerful enough to defeat Super Buu if it wasn't for his cockiness. Gotenks has the unique ability to go Super Saiyan 3 despite Goten and Trunks not being able to go Super Saiyan 3. Gotenks is later absorbed by Super Buu and Super Buu takes his powers.
The biological brother of Goku, and uncle of Gohan. He is sent to Earth to check if his brother Goku (Kakarot) had completed his mission of destroying Earth. Raditz is very sadistic and does not hesitate to attack his brother or kidnap his own nephew Gohan. Raditz is the first villain encountered in the Dragon Ball Z story. Raditz was killed by Goku and Piccolo. Goku sacrificed himself by holding him down so Piccolo could shoot Raditz with a Special Beam Cannon killing them both.
Nappa was an elite Saiyan warrior from the Planet Vegeta and is the sidekick of Prince Vegeta. Nappa is very big, powerful, and slow. He comes to Earth with Vegeta under orders from Frieza. Nappa is about 50 years old despite only looking 30. Nappa loves destruction and hurting innocents. Nappa took pleasure in bullying Gohan and torturing Piccolo and Krillin. Nappa is beaten by Goku and thrown to Vegeta's feet. Vegeta throws him into the air and kills him with and energy attack.
Zarbon and Dodoria
Zarbon and Dodoria are Freezia's right hand men. Zarbon has the ability to transform into a reptilian monster. Dodoria is killed by Vegeta on planet Namek, leaving Zarbon as the only elite warrior left at Frieza's disposal. Zarbon and Vegeta have a fierce fight, and Zarbon beats Vegeta. He then takes him to a chamber for questioning. When Vegeta recovers his strength he challenges Zarbon to another fight, this time beating him by sticking his arm through Zarbon's stomach and blasting him with a ki blast.
The Ginyu Force
Consisting of five members, Jeice, Burter, Recoome, Guldo, and their leader Captain Ginyu. They are first seen and Planet Namek while working for Frieza. They are famous for their dances, poses, and roll calls during battles. They are called to Namek to assist in the defeat of Vegeta. Vegeta kills the whole force besides Captain Ginyu, who switches bodies with a frog. Ginyu isn't killed until Kid Buu destroys Earth.
Frieza is of an unknown race and he runs the Planet Trade Organization. Frieza is the one that destroyed planet Vegeta and almost exterminating the whole Saiyan race. Frieza goes to Namek in order to find the Dragon Balls and wish for immortality. Frieza has four forms. Frieza toys with the Z-Fighters until Goku poses the only real threat to Frieza. Frieza then claims that he has only been using 50% of his true power and not even a Spirit Bomb could kill him. Frieza kills Krillin pushing Goku over the edge and becoming a Super Saiyan. Goku then has the upper hand against Frieza who uses a technique that will have Namek explode in 30 minutes. Frieza and Goku face off in an extremely long battle, Goku defeats Frieza with his own attack and when Frieza pleas for help Goku gives him enough energy to escape the planet, Frieza uses this energy to fire a final blast at Goku. Goku easily rebounds the attacks back at Frieza killing him.
Androids 16, 17, and 18
Android 16,17,and 18 were all created by Dr. Gero. Android 16 was the only one from this series of Androids that was purely synthetic, Androids 17, and 18 were both cyborgs. Android 17 goes rouge and kills Dr. Gero, then activates android 16 and sets of on a quest to kill Goku. Android 16, and 17 are killed by Cell in the Cell Saga but 18 survives and marries Krillin; they have a daughter together. Android 16's death is what sparked Gohan to go into a rage and become a Super Saiyan 2. In an alternate timeline android 17 and 18 killed Goku and the rest of the Z-Fighters besides Trunks.
Androids 19 and 20
Android 19 is the last Android made by Dr. Gero (Android 20) and comes with him everywhere. They are first seen destroying South City. 19 requests a fight with Goku and they fight. 19 is eventually killed by Vegeta's Big Bang Attack, and Android 20 is killed by a rouge Android 17.
Cell is the ultimate creation of Dr. Gero. He knows the attacks and fighting styles of many of the Z-Warriors. Cell is very sophisticated and intelligent, unlike many of the villains in the series. Cell has 4 forms. And to evolve to the next form he must absorb people via his tale. He absorbs android 17 first and tries to absorb 18 but she fleas. When he finally absorbs Android 18 he reaches his perfect form where his is able to asexual reproduce and create Cell Juniors. Cell starts the Cell Games, a tournament similar to the World Tournament. He is defeated by Gohan.
Dabura is the ruler of the Demon Realm and has been alive for thousands of years. He is Babidi's right hand man and thus does his bidding. He is first seen after the Z-Fighters leave from the World Tournament. He has special abilities that allow anyone his spit touches to turn to stone. He uses this ability on Piccolo and Krillin. Gohan is the first one to fight Dabura and controls the fight, enraging Dabura. After Buu is released Dabura mocks him so Buu turns him into chocolate and eats him.
Majin Buu is a pink, fat, warrior. His main purposes is to destroy worlds, he has the power to turn anything he wants into candy with his antenna. Buu also has the ability to regenerate himself after being blown to bits. Vegeta tries to kill Buu but his attempts are all in vain. Majin Buu is only surpassed in power by Super Saiyan 3 Goku and Goku can't hold the transformation long enough to defeat him. Buu makes unlikely friends with Hercule and adopts his own pet dog. When Buu's dog is killed he releases all of his evil as Evil Buu who eats him and creates Super Buu.
This form of Buu is more intelligent and more powerful, though he has fits of extreme rage and anger. Despite his already high power he can increase his power by using his absorption ability. Super Buu learns how to sense energy so he goes to Kami's Lookout and demands to fight their strongest fighter, Gotenks. Gotenks has capable of beating Super Buu but is too cocky and wastes all of his fusion time playing around with him. Super Buu absorbs Gotenks, and Gohan so the only people powerful enough to defeat Super Buu is Vegito, a fusion between Goku and Vegeta. Vegito almosts beats Super Buu but gets absorbed. While in there Goku and Vegeta free the absorbed warriors inside of him, Super Buu then becomes Kid Buu, the true and most evil form of Majin Buu.
Kid Buu is the true and most evil of all of the Buu forms. His first act of evil is destroying Earth. Super Buu then goes to the Other World to finish off Goku and Vegeta. Goku and Vegeta are no match for him, Goku at Super Saiyan 3 cannot even best him. Vegeta devises a plan to restore Earth and have Goku make a Super Spirit Bomb to destroy Kid Buu. When Goku makes the Spirit Bomb and launches it at Kid Buu, Kid Buu easily pushes the ball back towards Goku. Goku wishes to have his power levels restored and is finally able to push the Spirit Bomb back to Kid Buu. Kid Buu is destroyed by this and the world is saved.
Dragon Ball Z Sagas
Gohan's first combat experience comes against Raditz when he bursts out of Raditz's Space Pod and launches a powerful attack. Seeing this, Piccolo takes Gohan from his parents and trains him for the coming of Vegeta and Nappa. During the fight between the two Saiyans, Piccolo is destroyed by Nappa while protecting Gohan. This triggered Gohan to rapidly increase his power into one attack which slightly weakened and enraged Nappa but drained all the strength out of Gohan. At this time, Goku returns and continues the fight against Vegeta and Nappa.
During the final fight between Goku and Vegeta, Vegeta has Goku severely injured and unable to fight. Gohan returns to help his father but is proved useless against Vegeta. His tail finally grows back which was previously removed by Piccolo in safety of others, as the full moon was out, this triggered Gohan to transform into his Oozaru form which overpowers Vegeta.
Gohan's power and confidence increased as the Frieza saga progressed but was still unable to control and unlock his full potential of power. A friendship and close partnership with Krillin was formed and they both had to battle Captain Ginyu who had performed his body change technique with Goku which proved to be emotionally difficult at first. Gohan fought against Frieza alongside Krillin, Piccolo and Vegeta while Goku was recovering after the battle with Captain Ginyu. Although Gohan didn't fight much, Gohan's outbursts in power proved to be useful at the most dangerous of times. The first being when Frieza had transformed into his second form and attacked Krillin. Believing Krillin was dead, Gohan's power dramatically increased followed by a shower of Ki Blasts overwhelming Frieza. The second time is when Goku had transformed into a Super Saiyan and told Gohan to take Piccolo's unconscious body to the space ship and leave Planet Namek.
Gohan fought against Frieza alongside Krillin, Piccolo and Vegeta while Goku was recovering after the battle with Captain Ginyu. Although Gohan didn't fight much, Gohan's outbursts in power proved to be useful at the most dangerous of times. The first being when Frieza had transformed into his second form and attacked Krillin. Believing Krillin was dead, Gohan's power dramatically increased followed by a shower of Ki Blasts overwhelming Frieza. The second time is when Goku had transformed into a Super Saiyan and told Gohan to take Piccolo's unconscious body to the space ship and leave Planet Namek. While Goku had the upper-hand on the fight after transforming, he was caught by surprise by Frieza during a beam struggle which caused Frieza to throw an onslaught of attacks on Goku which made both Frieza and Gohan believe he had been defeated due to the disappearance of his power level. This worried Gohan and insisted he left the shuttle which was about to launch and fly back to the battlefield to find out what happened to his father. After being met by Frieza, he is told that Goku has been destroyed which outrages Gohan and throws a flurry of punches and a Ki Blast against Frieza. Goku's power level returned and continued the battle against Frieza telling Gohan to once again return to the space ship but before Gohan returned, he and all other beings on Namek apart from Frieza and Goku were transported to Earth following a wish granted by the Dragon Balls.
In preparation of the Androids arrival in three years time, Gohan trained with Goku and Piccolo. Another being created by Dr. Gero unexpectedly appeared which after Goku recovered from his heart condition, he took Gohan to the Hyperbolic Time Chamber so they could train in preparation for t he battle against Cell. Knowing Gohan had the power 'deep down' to defeat Cell and become one of the strongest fighters in the universe, Goku made it his intention to unlock and control Gohan's full potential during these intense training sessions. During this time, Gohan became able to transform into a Super Saiyan but Goku believed that although his current state still wouldn't be enough to defeat Cell, Gohan still had the potential to defeat him.
Shortly after the Androids invade Earth another super android comes named Cell. Cell is a very strong fighter who knows the moves and abilities of almost every Z-Fighter. Cell has 3(Maybe 4) stages. Imperfect Cell, Semi-Perfect Cell, Perfect Cell, and Super Perfect Cell. Cell has to absorb people/androids in order to raise his power level and become the next stage higher. The Z-Fighters train heavily in order to stop Cell but their efforts seem to be in vain since Cell keeps coming back. Cell proposes the idea for a tournament called the Cell Games. Everyone trains extensively for this tournament besides Goku and Gohan because they believe Goku is already strong enough to beat Cell as it is. A massive battle ensues and many of the Z-Fighters perish but in the end Cell is destroyed and the Galaxy is saved once again.
Great Saiyaman Saga
After the Cell Saga Goku enters the Other World Tournament and finishes with a draw against the warrior Pikkon. Back on Earth Gohan is now attending high school at Orange Star High School. Gohan becomes a vigilante crime fighter under the name The Great Saiyaman. In order to keep is identity under wraps he wears a ridiculous costume. His classmate and future girlfriend, Videl, figures out his real identity and decides not to tell anyone under the one condition that Gohan teach her how to fly and enter the upcoming World Tournament. At the World Tournament the Z-Fighters easily make it to the main event matches. Here is the first scene of Yamu and Spopovich, two Majin fighters who are trying to get energy for Babidi to release Buu.
Majin Buu Saga
After Yamu and Spopovich steal Gohan's energy they retreat to a spaceship and give the energy to Babidi. The Z-Fighters are hot on their tail and when they arrive Dabura attacks them, hindering the Z-Fighter's efforts. Vegeta, Gohan, Supreme Kai, and Goku all enter the spaceship. There they find out they have to beat three fighters in order to reach Babidi, they uses rock-paper-scissors to determine who will fight. The Z-Fighters progress through the gauntlet easily but Vegeta's dark heart allows him to become a Majin warrior himself. Vegeta and Goku fight while Dabura takes on Gohan and Supreme Kai. Majin Buu ends up being released despite the Z-Warrior's best efforts. Buu regenerates tissue and is a very strong warrior. Vegeta fights Buu but cannot best him. Later on Goku powers up to Super Saiyan Three and has his way with Buu but cannot hold the transformation long enough to defeat him. Buu kills Babidi and makes an unlikely friend in Mr. Satan. Buu finds a puppy and names it Bee, all is looking well since Buu has given up killing until...two men show up and shoot Bee.
Fusion Saga (Super Buu Saga)
Buu enraged by the killing of his dog blows out all of his rage in the form of steam. The rage forms into Evil Buu who kills the gunmen and then turns Buu into a piece of candy and eats him. Buu now becomes a less intelligent but extremely powerful Super Buu. Super Buu ravages Earth killing nearly everyone on the planet. At this time Piccolo teaches Goten and Trunks the Fusion Dance in order for them to fuse and become powerful enough to beat Super Buu. All while this is happening Gohan is on the Kai's world trying to unlock his true power. Super Buu flies to Kami's look out and challenges Gotenks to a fight. Gotenks goofs off the whole time instead of killing Buu right there so he gets away. Gohan comes back to Earth to fight Buu with his new powers but can't best him either. Super Buu absorbs Gohan and Gotenks. Goku comes back to Earth with special ear rings that allow two-people to fuse together for an unlimited amount of time. Goku uses these with Vegeta and they make Vegito. Vegito is controlling the fight with Super Buu until he gets turned into candy and eaten by Buu. Once inside of Buu Vegeta and Goku somehow defuse and go on a plan to free Gohan, Piccolo, Goten and Trunks. Once they free them Buu has a serious stomach ache and turns into his true form, Kid Buu.
Kid Buu Saga
Kid Buu's first act is destroying the Earth. Goku and Vegeta escape to the Other World only to be followed by Kid Buu. Goku and Vegeta are both bested by Kid Buu so Mr. Satan taunts Kid Buu, bringing out the Good Buu. Both Buu's fight and while this is happening Vegeta tells Dendai to go to Namek and wake the Dragon to wish for Earth to be back, he then tells them the plan to kill Kid Buu with a Spirit Bomb composed of all the energy of the people of Earth. Goku finishes the Spirit Bomb and fires it at Kid Buu. Goku does not have enough energy however to finish the attack. Dendai wishes for Goku's energy to be restored. Goku powers up to Super Saiyan and defeats Kid Buu, wishing that one day a good warrior as strong as Buu will be born, thus Uub is born. Goku also wishes that the people of Earth will forget about the whole Buu Saga so Good Buu can live on Earth freely.