Well, in some Naruto fanfictions, Bardock might be sealed by powerful jutsu. Maybe a dark ninja uses a forbidden sealing technique to lock him away, preventing him from interfering with their evil plans.
The balance of power in the Naruto universe of the fanfiction could be disrupted. If Bardock was a powerful force against some impending evil, his sealing could allow that evil to thrive. For example, if there was a powerful enemy that Bardock was meant to fight, with him sealed, the enemy could start to conquer and cause chaos more easily. Also, his friends or allies might start a quest to unseal him, which could lead to many adventures and encounters with other characters, both good and bad.
In some fanfictions, Kushina was sealed into Naruto through a complex jutsu. It might be a modified version of the sealing jutsu used to seal the Nine - Tails. The process could involve special incantations and chakra manipulations.
In some Naruto fanfictions, Madara might be sealed through a powerful jutsu created by the main character. For example, the protagonist could combine different elemental chakra natures to form a unique sealing technique specifically designed to counter Madara's power.
In this fanfiction, Naruto's character could be reimagined in multiple ways. Firstly, his power source might change. Instead of relying solely on chakra, he could have some Saiyan - like energy. His backstory could also be altered to incorporate Bardock's influence. For example, he might have a newfound sense of purpose related to the Saiyan race. His relationships might shift too. He could be more of a loner like Bardock was at times, or he might form new alliances with characters who are also connected to the Saiyan lore. This reimagining would create a whole new dynamic for Naruto's character development throughout the story.
If Naruto fused with Bardock in fanfiction, the story would likely take a very different turn. At first, Naruto might be confused by his new abilities and instincts. He would need to train to master them. As he does, he would become a more prominent figure in the ninja world. He could potentially change the balance of power. Enemies would be more afraid of him, and allies would look to him for leadership. His journey would be about not only protecting the village but also about understanding his new Saiyan heritage.
If other characters from both universes were involved, like Goku from Dragon Ball and Sasuke from Naruto. Goku and Naruto might get along really well because they both have a pure - hearted approach to fighting. Sasuke, however, might be more suspicious of Bardock and the Saiyan way. He might see them as a threat to his own power - seeking goals. Bardock, in turn, might not trust Sasuke's motives right away.
In many such fanfictions, it could be a variety of deities. It might be an ancient and powerful god from Naruto's world's mythology that the story's author has chosen to insert. For example, it could be a god of elements like a super - powerful fire god, which could give Naruto even more control over his existing fire - based jutsu and new, more extreme abilities related to fire.
Well, one reason could be that the author wants to explore an alternate universe. Maybe in this fanfiction's version of the Naruto world, the events leading to the sealing of the Kyuubi never occurred. It could be due to different political situations among the ninja villages, or perhaps a different chain of events that prevented the Kyuubi's attack on Konoha in the first place. So, without the attack, there was no need for the seal.
Well, Naruto might become more mysterious. Since Gaster is an unknown and rather enigmatic entity, Naruto could start having strange thoughts or powers that he doesn't fully understand at first. He might seem more withdrawn as he tries to figure out what's going on inside him, and his normal cheerful and straightforward personality could be clouded by the presence of Gaster.
It could completely change the direction of the plot. If the echidna is released, it might bring a new type of power or threat into the Naruto world that the characters have to face.