Goku was initially intended to be a cyborg in the Dragon Ball series, but he ultimately became an alien. Akira Toriyama's manga, The Adventures of Tongpoo, which served as a precursor to Dragon Ball, featured a cyborg protagonist reminiscent of Goku. Toriyama frequently incorporated androids and cyborgs into Dragon Ball, highlighting his preference for these characters in his narratives.
Goku, known as an alien Saiyan in DBZ, was originally conceived by Akira Toriyama as nearly a cyborg, as evidenced by his 'prototype' in a prior series. Dragon Ball Z introduced many prominent cyborgs and androids like 17, 18, Cell, and even Frieza, but Goku, initially envisioned as a cyborg, was a surprising twist. Goku, famously a Saiyan from Planet Vegeta, was initially planned as a cyborg based on his earlier incarnation in Toriyama's work before Dragon Ball.
In the early chapters of Dragon Ball, Goku is introduced as a young child scavenging for food in the wilderness. Originally arriving on Earth in a spaceship and raised by his adoptive father, Gohan, Goku's solitary life changes when he encounters Bulma during her quest for the Dragon Balls. Bulma's failed attempt to shoot Goku reveals his bulletproof nature, leading them to team up to find the Dragon Balls. This laid the foundation for Dragon Ball, revealing Goku's eventual Saiyan heritage, mirroring his 'prototype', Tongpoo, step by step.
Toriyama's earlier manga, The Adventures of Tongpoo, which closely resembles Dragon Ball, features Tongpoo, a nearly indestructible cyborg who meets Plamo on a deserted planet. Paralleling Goku's story, Tongpoo is shot by Plamo upon their first meeting, much like Bulma's encounter with Goku. The similarities in character design and storyline between Tongpoo and early Goku highlight how closely Goku came to being a cyborg.
While Toriyama ultimately chose to make Goku a Saiyan in Dragon Ball Z, he continued to incorporate android and cyborg characters like 17, 18, and Cell into the series. This affinity for robotic characters is evident throughout Toriyama's work, including the influential presence of Android 8 in the original Dragon Ball series.
Despite the deviation from making Goku a cyborg, Toriyama's early creation of Tongpoo in The Adventures of Tongpoo significantly influenced the Dragon Ball universe. It underscores Toriyama's creative process and his enduring fascination with androids and cyborgs, shaping the narrative evolution from Tongpoo to Goku's final Saiyan form.
In summary, while Goku's journey evolved from cyborg prototype to Saiyan warrior, the influence of Toriyama's earlier work in The Adventures of Tongpoo remains palpable throughout Dragon Ball's rich storytelling tradition.