He would probably be frustrated. Batman relies on his human abilities and technology, not powers. He might try to quickly correct their misunderstanding.
At first, Batman might be bemused by the Justice League's assumption. But then he'd realize the potential problems it could cause. If they think he has powers, they might expect him to perform in ways that are beyond his capabilities. He'd have to set the record straight, but in his own Batman - like way. He might show them the inner workings of his gadgets or give them a detailed rundown of his training regime to prove that he's just a man, albeit a very highly - skilled one.
Batman would likely be annoyed. He prides himself on being a normal human who has achieved great things through hard work and determination. So, if the Justice League thought he had powers, he'd first feel insulted that they didn't recognize his true nature. Then he'd probably go into a long - winded explanation about how all his feats are the result of training, intelligence, and his gadgets. He might even use it as an opportunity to lecture the Justice League on not making assumptions.
Maybe Batman's extreme combat skills and strategic genius are so amazing that the Justice League mistakes them for powers. He can take on foes much stronger than him and always seems to have a plan, which might seem superhuman.
The Flash might initially be in denial. He's used to Batman always having a plan and his death would be a huge shock. He would then turn his speed into a tool for investigation, trying to find out exactly what happened. Green Lantern could feel a sense of loss but also be spurred into action, using his ring to try and prevent future tragedies like Batman's death. He might create constructs in Batman's memory to inspire the team.
The Justice League as a whole would have a diverse range of reactions. Some members like the Flash would be all for it, seeing it as a fun exploration of Batman. Others like Wonder Woman might use it as a way to understand how the public perceives Batman's role in the League. And then there are those like Aquaman who might just shrug it off unless it directly affects his interests. The fanfiction could also potentially create some internal discussions within the League about how they are all portrayed in the public's imagination.
They might have a range of reactions. Superman could be amused or a bit confused by some of the wilder interpretations of Batman. Wonder Woman might find it interesting to see how fans perceive the Dark Knight's world. Flash might laugh out loud at some of the more comical fanfictions.
The powers could combine in many ways. For example, Superman's super strength could be used to enhance Voltron's physical attacks. The Flash's speed could help Voltron move faster in combat. And the Voltron lions' unique abilities like the Black Lion's leadership and the Blue Lion's water - based powers could be used in conjunction with the Justice League's powers. Maybe the Blue Lion could create water barriers while Aquaman controls the water within to make it more powerful.
Some might be shocked. For instance, Batman is often portrayed in very different ways in fanfiction compared to his 'canon' self. Superman might raise an eyebrow at a fanfic where Batman is overly emotional. Others like the Flash might be really into it, finding the different takes on Batman's character and his adventures exciting.
In many Justice League fanfictions where Batman dies, it could lead to a complete shift in the team dynamics. For example, the League might become more reckless without Batman's strategic mind. Superman could struggle with the loss, perhaps blaming himself for not being able to protect Batman. The other members like Wonder Woman would have to step up in terms of leadership and planning. It could also open the door for new characters to emerge in the fanfiction's storyline, trying to fill the void left by Batman.
They could learn something new about Batman. Fanfiction often explores different aspects of a character that might not be shown in the official comics or movies. The Justice League may discover new traits or backstories of Batman through the Lego - inspired fanfiction. For example, they could see how fans imagine Batman's relationships in a more light - hearted Lego - style setting.
Spiderman's powers of super strength, agility, and his spider - sense could combine well with the Justice League's powers. For example, if Superman were in a fight and Spiderman was there, Spiderman could use his spider - sense to detect a hidden threat while Superman was dealing with the main villain, and then his agility would allow him to quickly move in and neutralize it.
Naruto's chakra - based powers like the Rasengan could be combined with Diana's superhuman strength. For example, Naruto could create a Rasengan and Diana could use her strength to throw it at an enemy with even more force.