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.
Maybe Bardock's past and his own struggles in the Dragon Ball universe could parallel Naruto's journey in some way. For example, both are from warrior - like races (Saiyans and the Uzumaki clan which has a reputation for being strong). Their fates could be intertwined as they face challenges together. Bardock could teach Naruto some of his Saiyan fighting techniques, which Naruto could then adapt to his own ninja style.
Well, he would probably become extremely powerful. His already impressive chakra reserves would be multiplied many times over with the Juubi's power. He might gain new and unique jutsu that are a combination of his own and the Juubi's abilities.
Often, the Akatsuki still remain as main antagonists. Since Naruto's fusion with the Kyuubi makes him more powerful, they would be even more interested in capturing him for his power.
Well, it would be an extremely powerful combination. Naruto has his ninja skills and chakra, while Broly is a Saiyan with insane strength. Maybe they'd create new and unique fighting techniques. Their fused form could have Naruto's determination combined with Broly's raw power, making them a force to be reckoned with in the fanfiction universe.
In such a fanfiction, Naruto's powerful chakra could be combined with Madara's Uchiha abilities in really interesting ways. Naruto might gain new Sharingan - like powers or be able to use some of Madara's signature jutsu more effectively. And their combined strength would probably make them nearly unbeatable in battle, changing the power dynamics in the Naruto universe completely.
One of the popular pairings is Naruto and Hinata. Their relationship has a strong foundation in the original series, and in fused fanfiction, it can be explored in new and exciting ways, especially when fused with different settings or storylines. Another popular pairing is Sasuke and Sakura. Their complex relationship offers a lot of room for creativity in fanfiction, like fusing their story with a time - travel plot. Kakashi and any female character also tend to be popular in some fused fanfictions, as Kakashi is a very beloved character with a mysterious past that can be intertwined with other characters in interesting ways.
One interesting concept could be fusing Naruto's world with another popular anime world. For example, fusing it with the world of One Piece. Imagine Naruto characters having to deal with Devil Fruits and the Grand Line. Another concept might be fusing different ninja clans in unique ways within the Naruto universe itself, like creating a new type of jutsu that combines the powers of the Uchiha and Hyuga clans. Also, fusing Naruto with a modern - day setting, where ninjas have to adapt to technology while still using their chakra abilities.
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.