Maybe it's a new character created specifically for the fanfiction. This character could be a powerful sorcerer who has the ability to manipulate people's minds. He targets Goku out of jealousy for his power and popularity. By using his mind - control powers, he makes everyone around Goku believe that he's a traitor, thus making himself the main antagonist.
Another possibility is that it could be a corrupted version of one of Goku's closest friends. Let's say Vegeta gets corrupted by some dark power. In his corrupted state, he turns everyone against Goku. He uses his influence and his knowledge of Goku's weaknesses to make the others believe that Goku is a danger to them, making the corrupted Vegeta the main antagonist.
Chapter 722, "It's Time to Tell Him the Truth", is the clearest early answer because the hidden truth stops feeling like mere subtext. The chapter gives readers a real answer by opening on The comment section was also in shock.
Chapter 627, "Definitely Not an Accident", is the clearest early answer because it turns Bai Lu's situation into a concrete plot event. The chapter turns that into something concrete by moving from He looked at the sinister smile lingering in Jiang Li's eyes, then at...
Chapter 841, "Isn't this Daniu?", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. The chapter gives readers a real answer by opening on Zhao Lang took the photograph and glanced at it, chuckling, "It...
Chapter 696, "I Am a Very Narrow-Minded Person", is the clearest early answer because the buildup finally cashes out in a real clash. The chapter turns that into something concrete by moving from But she heard Jiang Li say, "Mom, you don't need to be anxious, I'm...
If you want the clearest chapter reference, go to Chapter 23. Early on, Although Jiang Li exerted very little strength, Jiang Yan instantly felt...; later, the chapter leans on The pain twisted his face grotesquely as he dove headfirst into the sofa..
Chapter 934, "Gu Pansheng's Grace [Extras: Protagonist's Edition]", is the clearest early answer because it turns Great Grandpa's situation into a concrete plot event. The chapter turns that into something concrete by moving from Twenty minutes later, Jiang Shixu had finished cooking.
The best chapter pointer here is Chapter 22, "Number 7203". It opens with Hearing this, Su Yinwan looked at Shang Shaojing with a face full of... and closes on Jiang Li's righteousness temporarily shut Jiang Yan up, but after a few....
Chapter 600, "You merchants aren't even fit to carry my shoes!", is the clearest early answer because it turns Mrs's situation into a concrete plot event. The chapter gives readers a real answer by opening on Shen Ruobing was not deaf to the ironic tone in Jin Siyue's comments,...
Chapter 726, "She Has Already Tried to Keep a Low Profile", is the clearest early answer because it turns Yu Li's situation into a concrete plot event. The chapter gives readers a real answer by opening on Su Yinwan was using the money she had recently acquired to boost...
The best chapter pointer here is Chapter 20, "Miss Su, your defense is somewhat clumsy". It opens with Several people turned their heads upon hearing the sound and saw three... and closes on So, he turned and questioned Jiang Li..