Raditz (ラディッツ, Radittsu) is the son of Bardock, and the older brother of Kakarot (Goku). With him being Goku's brother. He is the uncle of Gohan and Goten. He is also the granduncle of Pan and ancestor of Goku Jr. Raditz arrives on Earth in search of a man named "Kakarot," later revealed to be Goku. Raditz has a long rock star hair style and is only seen wearing Saiyan Armor. After he incapacitates a farmer who challenged him, Raditz detects a power reading on his scouter and assumes it's Goku. He tracks down the source of the energy and comes face to face with Piccolo, Goku's enemy at the time. Raditz asks Piccolo where he can find "Kakarot", but Piccolo refuses to tell him, warning him to leave Earth at once. Raditz laughs at Piccolo, who fires a powerful attack at Raditz, leaving him unscathed, only managing to "singe some of his leg hair," as Raditz puts it. Just as Raditz prepares to destroy Piccolo, he detects another power level, and this time, he knows that it as Kakarot, the one he is looking for. He also calls Goku Kakarot all the time.
Beginning of Dragon Ball Z
In the beginning of Dragon Ball Z, Raditz arrives on Earth in search of a man named "Kakarot," later revealed to be Goku. After he incapacitates a farmer who found his space pod, Raditz kills him, by flicking his own bullet right back at him. Raditz detects a power reading on his scouter and assumes it is Goku. He tracks down the source of the energy and comes face to face with Piccolo, Goku's enemy at the time. Raditz asks Piccolo where he can find "Kakarot", but Piccolo refuses to tell him, warning him to leave Earth at once. Raditz laughs at Piccolo, who fires a powerful attack at Raditz, leaving him unscathed, only managing to "singe some of his leg hair," as Raditz puts it. Just as Raditz prepares to destroy Piccolo, he detects another power level , and this time, he knows that it is Kakarot, the one he is looking for.
Raditz tracks the power level down to the Kame House, where Goku, his son Gohan, Bulma, Krillin, Master Roshi, and Turtle are enjoying a reunion. Raditz identifies Goku as Kakarot, and informs Goku that he is his big brother, who arrived on Earth to find him. When Goku asks where Raditz came from, Raditz tells Goku that they are both Saiyan warriors, and tells him the history of the Saiyan race including the Planet Trade Organization's practice of conquering planets and selling them for profit. Goku and Krillin express their disgust at Raditz and tell him to leave. When it becomes clear to Raditz that Goku is not coming with him, Raditz kidnaps Gohan (who still has a Saiyan tail) and holds him for ransom. He informs Goku that if he ever wants to see Gohan again, he should eliminate one hundred Earthlings and bring them to Raditz by the next day. Laughing, Raditz flies off with Gohan in his hands.
Later, he shuts the crying Gohan in his spacepod, unable to stand his crying. Raditz is surprised to find that his scouterreported a power level of 710 for Gohan, which Raditz dismissed as a malfunction because it would mean that the child was even stronger than his father. Shortly afterwards, Raditz sees Goku and Piccolo who have joined forces to beat him, and since his scouter accurately warned him of their approach, he came to the realization that Gohan may actually be as strong as his reading said. As he lies dying, Raditz genuinely acknowledges Goku's death (as well as his own), but Piccolo tells him about the Dragon Balls that will revive Goku shortly after the wish is made. Raditz, however, retorts that his scouter is also a transmitter, and his two Saiyan friends have heard everything and will come for the Dragon Balls to wish him back. Laughing his head off, Raditz is finished off by Piccolo, and dies shortly before Goku does so. Using his scouter to transmit Piccolo's message, Raditz calls for help from his two fellow Saiyans, Nappa and Vegeta, who eventually journey to Earth to gather the Dragon Balls, not to revive Raditz (as Raditz believed), but for immortality. In the Other World , Raditz attempts to fight King Yemma , who overpowers him and sends Raditz to Hell .
After Goku dies, Bulma and Krillin remove Raditz's scouter from his corpse (which remains unseen). Bulma modifies the scouter so it can read actual numbers rather than the strange symbols that represent numbers. The scouter later explodes when Goku powers up during his fight with Vegeta. In an anime only flashback, Krillin reminds Raditz telling that the Saiyans capture and sell planets, and deduce that Frieza and his soldiers must be part of what he called the "Planet Trade".In an anime only flashback, Raditz, along with Nappa and Vegeta return from their conquest on Planet Shikk. However, they are met with insult rather than congratulations by Dodoria , Zarbon , and Frieza . While Raditz is visibly hurt and angered at this, Nappa loses control and tries to attack Frieza along with Zarbon and Dodoria, but Vegeta orders his comrade to stand down, knowing that he wouldn't stand a chance against them.