In the fanfiction, Bardock might be in a state of awe. Goku's fight against Buu is no small feat. Bardock would likely note Goku's ability to keep getting back up, no matter how hard Buu hits him. He might also be thinking about the power levels involved. In his time, the power levels he knew were much lower. Now, seeing Goku take on a foe as powerful as Buu, he'd realize just how much the Saiyan race has evolved, especially with Goku as a prime example.
In the fanfic, Bardock might be filled with pride. He could be thinking how his son has grown into such a powerful warrior. After all, Goku has come a long way from being a little Saiyan baby sent to Earth. Watching Goku fight Buu, Bardock might see all the potential he always knew Goku had, finally being fully unleashed.
His presence can add an emotional depth. It could be a moment of connection between father and son, even if Goku doesn't know Bardock is there. It might also serve as a reminder of Goku's Saiyan heritage.
Well, Naruto himself might be really focused on Pain's motives in the fanfiction fight. Since he always tries to understand his opponents. Sasuke could be analyzing Pain's jutsu and thinking about how it compares to his own power. And Sakura might be worried about the destruction caused, just like she was in the original story when Pain attacked the village.
It could potentially influence Goku's fighting style. Bardock was a fierce warrior with his own set of techniques. Goku may subconsciously incorporate some of Bardock's fighting spirit or even mimic some of his moves. Also, Bardock's presence could be a source of inspiration for Goku, making him come up with new strategies on the fly during the fight against Buu in the fanfic.
At first, it could be a bit rocky. Bardock is used to the harsh Saiyan ways, while Goku has been raised on Earth with different values. But as they spend time together, they start to understand and respect each other. Bardock could become a mentor to Goku, teaching him advanced Saiyan fighting techniques and Goku could teach Bardock about friendship and love.
At first, it might be tense. Bardock is a hardened Saiyan warrior from a different era, and Goku has grown up on Earth with a very different set of values. But as they start to communicate, they would find common ground in their Saiyan blood. Goku's pure - heartedness could gradually win over Bardock, and Bardock's strength and pride could earn Goku's respect.
The Justice League would be in for a revelation. Goku's 'I Am' speech is not just about power but about self - discovery. They'd notice how Goku's values are different from their own in some ways. For example, Goku's focus on personal growth through combat. They might also be inspired to be more open about their own identities and not be so bound by their superhero personas.
They might be quite surprised. Some characters could find it strange to see their own stories being reimagined in different ways by fans. For example, if Sherlock Holmes were to watch elementary fanfiction, he might be intrigued by the new interpretations of his deductive reasoning skills or his relationships with other characters like Watson.
The characters might also feel a sense of flattery. If they see that the fanfiction writers are so passionate about their world and go to great lengths to create these stories. Kristoff, for instance, might be happy that fans are interested enough in his character to include him in different adventures in the fanfiction, even if those adventures are a bit far - fetched from his real - life (in - the - movie - life) experiences.
He might be really surprised. He could find it strange to see different versions of his own story and the people around him in the fanfiction.