If there is any character in Dragon Ball that could be considered Goku’s “mentor,” it would undoubtedly be Grandpa Gohan. Grandpa Gohan is an exceptionally kind-hearted and loving figure who took care of Goku when he found him in the woods. Goku’s personality and determination are greatly influenced by this nurturing grandfather.
Grandpa Gohan is one of the characters in the series who does not appear often, yet he is cherished by many fans. His significance is particularly highlighted in the latest fan-made discussions circulating on the internet.

Moreover, many fans believe that Bandai Namco should include Grandpa Gohan in Dragon Ball: Sparking Zero (the highly anticipated sequel to Dragon Ball Z: Budokai Tenkaichi 3). Without him, fans would surely feel disappointed. It’s clear that without Grandpa Gohan, Goku could have become a lost soul wandering the Earth until his very existence faded away.
In the original storyline, Goku is sent to Earth with the mission to exterminate humanity and conquer the planet. Unfortunately, upon landing on Earth, he falls into a ravine and suffers a head injury, causing him to lose his Saiyan instincts. Thus, the nurturing aspect of humans, especially from Grandpa Gohan, shapes Goku and restores his martial arts knowledge. Eventually, Goku grows into a new person with a pure heart and a determined spirit, committed to protecting the Earth.
In a lively discussion on the social media platform Reddit, a fan named PerfectDecayRM shared an image of Goku’s nurturing grandfather and emphasized the game’s potential failure if he is not included in Bandai Namco’s lineup.

Sparking Zero already has numerous character slots filled. However, unlike many characters such as Frieza, Cell, and Vegeta, who dominate gameplay due to their transformation abilities, only one slot remains open for Grandpa Gohan.
Since Grandpa Gohan has been a playable character in both Budokai Tenkaichi 2 and Budokai Tenkaichi 3 (two action-adventure games based on the famous Dragon Ball Z series), it is highly likely that he will make a return in Dragon Ball: Sparking Zero as fans desire.