Grandpa Son Gohan
From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Grandpa Son Gohan (孫 悟飯 じいちゃん, Son Gohan Jiichan; FUNimation "Grandpa Gohan", Viz "Son Gohan") is the adoptive Human grandfather of Son Goku. He is often referred to as "Grandpa Son Gohan" to separate him from the more popular Son Gohan character, who is named after him.
Grandpa Gohan was a loving and caring man who became the adoptive grandfather of Goku when he found him near the landing site of Goku when he was a baby. When Goku first landed on Earth, his mission was to, in time, destroy the entire human race and sell the planet to another race. Being a Saiyan, who are known to be very aggressive and short-tempered, Goku was very uncooperative at first (in the Bardock special, he simply laughs as Grandpa Gohan found him in the wilderness). But after falling into a ravine, Goku hit his head, causing him to lose his memory, and became a regular happy, loving boy. Grandpa Gohan was taught martial arts by Muten Roshi and passed on his knowledge to Goku. Grandpa Gohan warned Goku to never look at a full moon and to stay indoors on nights of one – implying that he had already transformed before and Grandpa Gohan managed to survive the first time. He followed his advice for sometime until one night (as Goku explained to Bulma, Yamucha, Puar, and Oolong what happens when he looks at a full moon while they were held in prison at Castle Pilaf) when Goku stepped outside to relieve himself. He then glanced at the full moon, transforming into a Great Ape, and went on a rampage, killing Gohan, though because Goku did not remember what he did when transformed he was not aware of it. From that time on, Goku believed that Grandpa Gohan was killed by a monster and that his soul was in the Four-Star Ball. In Dragon Ball Z, when Goku was battling Vegeta as he transformed into a Great Ape, Goku finally realized that he had killed Grandpa Gohan when he was little.
 Fortuneteller Baba Saga
During the Fortuneteller Baba Saga, Goku, Yamucha, Muten Roshi, Upa, Puar, and Kuririn must fight Fortuneteller Baba's five fighters in order to find the last Dragon Ball. Goku is the last one left to fight and Fortuneteller Baba brings out a "special" fighter as her last. The last opponent is a mysterious man wearing a rabbit mask. Muten Roshi then realizes that the man is Goku's dead grandfather, Grandpa Gohan. The others are baffled as to why he is pounding and pounding on Goku. After unintentionally ripping Goku's tail off, Grandpa Gohan surrenders and explains that he was trying to make a point to Goku that he needed to train harder and make his tail work for him instead of against him, and through these words Goku realized his identity. Seeing no reason to continue concealing his identity, Gohan unmasks himself, leading to an emotional reunion. Gohan and Baba go on to explain that Baba has the power to bring the dead back to life for one day. Bulma then explains the Dragon Balls and her adventures with Goku to Grandpa Gohan. Grandpa Gohan is quite content with "life" in the Next World, and thus chooses to remain dead, vanishing after thanking Roshi for teaching Goku and giving his grandson a final farewell. It appears that Grandpa Gohan possesses some of Muten Roshi's perverted traits, as he states, "I've got a lot of friends, and most of them are brunettes."
 Goku's and Chichi's wedding
Although filler, Grandpa Gohan makes another appearance in the anime. In the final two episodes of Dragon Ball, Goku and Chichi have been in the middle of a quest to lower a new fire engulfing Mt. Frypan with Ox-King trapped inside protecting Chichi's wedding dress. Goku and Chichi come upon the gateway between the living world and the next, making their way past numerous illusions, they find themselves in the cave of the Spirit Furnace. They end up meeting up with Grandpa Gohan, whom Goku mistakes for being the legendary furnace keeper Annin. Grandpa Gohan is actually a bodyguard for Annin, as well as protecting the lever that can turn off the Spirit Furnace. After a small scuffle with Annin, Goku is allowed to travel into the depths of the furnace where he's able to patch the leak. Goku bids a final farewell to his grandfather as he and Chichi move on into the beginning of wedded bliss.
 Dragon Ball Z
While seen only through flashbacks, Grandpa Gohan appears quite a few times through out the DBZ series. Out of three known flashbacks, the first is when Master Roshi tells Goku of Grandpa Gohan's story of finding him. Through this flashback, it's insinuated that Goku's first "off-screen" Great Ape transformation occurred after his arrival upon Earth and following a first glimpse Grandpa Gohan had of him (explaining why in Bardock: The Father of Goku, Grandpa Gohan picks up Goku to take home among leveled trees in daylight, in contrast to first seeing him in his infant ship at night, and also why he clearly knew of the transformation in the Dragon Ball series). Later, another flashback takes place where Goku recalls a pre-Dragon Ball moment of his grandfather warning him to never go outside on the night of a full moon after he sees Vegeta transform into a Great Ape. When Goku sees this, he came to realize that when he transformed, he was the one that killed Gohan. The final flashback of him comes much later in the series wherein Goku fondly remembers being found by Grandpa Gohan (a sequence originally shown in the Bardock special, upgraded in animation in a sepia color-tone) followed by a short sequence of Grandpa Gohan's training that raised Goku into a boy "trained like steel".
 Dragon Ball GT
Grandpa Gohan makes one small appearance during a flashback that Goku has at the end of the Dragon Ball GT series. Grandpa Gohan is seen holding Goku up in the air during Goku's final walk outside the World Martial Arts Tournament arena.
 Dragon Ball: The Magic Begins
In the unofficial live action movie Dragon Ball: The Magic Begins, Grandpa Gohan (known as "Sparkle" in the movie) is alive and trains with Goku, then is captured by villains searching for his Dragon Ball.
 Dragonball: Evolution
Main article: Gohan (Randall Duk Kim)
The plot line obviously varies from the original series.
 Video games
Grandpa Gohan is a boss in Dragon Ball: Advanced Adventure. Afterwards, he is a playable character in Free Battle mode. After finding him in Extra mode, he becomes a playable character in all available modes. Grandpa Gohan is also a playable character in both Dragon Ball Z: Budokai Tenkaichi 2 and Dragon Ball Z: Budokai Tenkaichi 3 and wears the Fox mask he once donned in Dragon Ball (though it is knocked off when he is damaged enough). He also appears in Dragon Ball Online in the first story quest.
- Turtle School Tranquility – Grandpa Gohan's ultimate attack in Budokai Tenkaichi 2. Grandpa Gohan kicks his opponent into the air, flies toward them, and then kicks them downward. While his opponent is still falling, Grandpa Gohan performs the Jan-ken on them.
 Voice actors
- Japanese dub: Osamu Saka (Most media), Jinpei Azusa (Bardock: The Father of Goku), and Shigeru Chiba (Dragon Ball Kai)
- FUNimation dub: Christopher Sabat
- Ocean Group dub: Michael Donovan
- Grandpa Gohan's voice is heard in the Ocean Group dub of "The Secret of the Dragon Balls" saying his last words and is the only time he is heard due to that dub being canceled way before the episode he debuts in.
- Grandpa Gohan apparently had an appetite similar to Goku's. In "Dress in Flames", Ox King comments that Goku shares his grandfather's fierce appetite, though since it would later be revealed Goku was a Saiyan this is just a coincidence.
- The mask Grandpa Gohan wears was originally seen worn by Nejishiki in Dr. Slump.
- Goku once said he knows karate, which means Grandpa Gohan must have known karate as well and taught Goku.
- Goku has grown up thinking that Grandpa Gohan's spirit rests within the Four-Star Ball. He thinks this because it was his most prized possession before he died.
- Goku's son, Gohan, is named after his grandfather only because the baby went without a name for awhile until the name "Gohan" came into conversation and the baby laughed because he liked the name. Chichi, Goku, and the Ox-King decided to name him that.