In the fanfiction, the plot could develop such that the power of the universe's watch attracts other villains or powerful beings. They might try to steal the watch from Goku during his battle with Jiren. This would add a new layer of complexity as Goku has to fend off these new threats while still trying to defeat Jiren.
In this fanfiction, Goku vs Jiren is likely to be an epic battle. Goku's power with the Universe's Watch might bring new and unexpected abilities. Jiren, on the other hand, is an extremely powerful opponent. The fight could involve intense energy blasts, high - speed combat, and strategic maneuvers. It might also explore the growth of Goku's character and his newfound power in relation to Jiren's unwavering strength.
One possible plot twist could be that Jiren discovers a way to nullify Saitama's strength. Maybe he finds some sort of energy - draining technique that weakens Saitama over time. Another could be that Saitama holds back for some reason, like he wants to see the full extent of Jiren's power, and in doing so, he gets into a real struggle.
A plot development could be that Gaara and Sasuke start the fight. Sasuke tries to taunt Gaara about his past and how he could never truly understand Sakura like he does. Gaara, in response, shows his determination through his sand attacks. As the fight progresses, Sakura starts to see a side of Gaara she never knew, which makes her question her feelings for Sasuke. Meanwhile, Sasuke becomes more and more frustrated as he realizes he might be losing Sakura's attention, which makes him fight even more recklessly.
In the 'bardock sees goku as a god' fanfiction, a plot development could be that Bardock's belief in Goku as a god gives Goku new powers or a new level of confidence. This could lead to Goku taking on more dangerous foes. Or perhaps Bardock tries to build a temple or shrine for Goku. There could also be a conflict where some villains try to use Bardock's blind faith in Goku to their advantage by tricking him into leading them to Goku.
For Goku, he could gain a deeper understanding of his heritage. Meeting Bardock would make him more aware of his Saiyan side. He might become more confident in his Saiyan abilities. For Bardock, seeing Goku all grown up and powerful could give him a sense of peace. He could realize that his sacrifice was worth it and be proud of the man his son has become.
Yes, Goku manages to defeat Jiren in the manga after an intense battle and showing great determination and growth in his powers.
Goku could develop a deeper sense of his Saiyan identity. Knowing his father, he might start to embrace more of the Saiyan warrior spirit. Bardock might change too, seeing the good in the universe through Goku's eyes.
One possible storyline could be that Naruto is somehow transported to Goku Black's universe. There, he has to face Goku Black who sees him as an intruder. Naruto would have to quickly learn about Goku Black's powers and find a way to fight back using his ninja skills. Another storyline could be that a powerful villain creates a rift between their two universes and pits them against each other. They start off as enemies but then realize they are being manipulated and team up to fight the real villain.
There could be a storyline where Beerus, out of boredom, decides to train Goku Black instead of fighting him. But Goku Black misinterprets this as a sign of weakness and attacks Beerus. This could lead to a battle where Beerus has to hold back at first to avoid killing Goku Black, but as the fight progresses, he realizes he has to use his full power to subdue him.
Well, perhaps in the 'naruto vs sasuke the aftermath fanfic', there could be a focus on the physical and mental recovery of both Naruto and Sasuke. Naruto, being the more positive of the two, might bounce back quickly, but Sasuke's internal struggles could be explored in depth. There could also be new threats emerging that they have to face together, which would force them to put aside their differences and cooperate, even if reluctantly at first.