He could be more cunning and strategic, constantly plotting against his opponents in the Tournament of Power.
In fanfiction, his personality might be made more complex. He could show moments of hesitation or self - doubt during the Tournament of Power. Maybe he starts to question his own motives and the path he has chosen. This would add a new layer to his character compared to the straightforward villainy in the original series.
Some fanfictions might portray Goku Black as having a sense of honor in the Tournament of Power. He could choose to fight fair against certain opponents, respecting their strength. He may also have a more sarcastic and taunting side, using words to get under his opponents' skin before attacking. This would make him not just a power - hungry villain but also a character with more depth, as he engages in psychological warfare during the intense battles of the Tournament of Power.
He would add more chaos. Since he's a powerful and unpredictable character, his actions would disrupt the normal flow of the tournament. He might target strong fighters first to gain an advantage.
In some fanfictions, Goku Black has been depicted as having a hidden power reserve. In the Tournament of Power, he could tap into this reserve and achieve a new level of transformation. This new form would give him increased speed, strength, and energy projection. He might use this form to take on multiple strong opponents at once, like the powerful warriors from Universe 7 or other universes. His attacks could become more unpredictable, such as his energy beams changing direction mid - flight to catch his foes off - guard.
In fanfiction, Goku Black might have some unique power - ups during the Tournament of Power. He could tap into a new form that's even more menacing than his regular state. This would give him an edge over his opponents and make for some exciting battles. He might also use his wits and manipulation skills to turn the other fighters against each other.
Hit would also make for a fascinating pairing. Hit is a skilled assassin with time - manipulation abilities. He could be a great foil to Goku Black. Maybe Goku Black tries to outwit Hit in his time - stop techniques, or they could form a temporary alliance based on their mutual desire to eliminate certain opponents in the tournament. There would be a lot of cat - and - mouse action between them.
I think Broly could also be a really tough opponent. In his Legendary Super Saiyan form, he has incredible power and his rage - driven fighting style could give Goku SSJ4 a hard time in the Tournament of Power. Broly doesn't hold back and his raw power could potentially overpower Goku if he's not careful.
One idea could be that Goku Black forms an unexpected alliance during the Tournament of Power. Maybe he teams up with a weaker universe's fighter out of a sense of pride, thinking he can make them strong enough to be a worthy opponent. Another could be that Goku Black discovers a new form during the tournament that is unique to this alternate version of himself.
In some fanfictions, Naruto's Six Paths Power is portrayed as having a darker side. Maybe it corrupts him a little, making his decisions more morally ambiguous. This is different from the original where he was always the hero with a clear moral compass.
Their relationship could be portrayed as more of a brotherly bond. Goku could be like an older brother to Gohan, showing him the ropes of being a Saiyan and having fun adventures together.
One interesting plotline could be Goku discovering a new form during the Tournament of Power in the fanfiction. This form might give him an edge over the other powerful opponents.
Vegeta can also be extremely powerful in these fanfictions. He's constantly striving to be stronger than Goku and might gain some new abilities or techniques for the tournament. Another character could be Jiren. In the original Tournament of Power, he was a very tough opponent, and in fanfiction, he might be even more powerful or have some different backstory that makes him a formidable force.