There could be new villains from the cosmos. Since Naruto is the son of Galactus, other cosmic entities who oppose Galactus might target Naruto. For example, some powerful alien race that wants to get rid of any trace of Galactus' bloodline. They could send their most powerful warriors to the ninja world to take on Naruto.
Perhaps in this fanfiction, Naruto's origin as the son of Galactus is a secret at first. As he grows up, he starts to have strange dreams or experiences that lead him to discover his true heritage. This discovery could then lead to a whole new arc in the Naruto story. He could then seek out knowledge about Galactus and his powers, and along the way, face challenges from those who want to use his powers for their own gain or those who want to destroy him because of his connection to such a powerful being.
Well, it could center around Naruto coming across knowledge about Galactus. He could start to idolize Galactus' ability to control cosmic forces. Naruto might then attempt to incorporate some of those ideas into his own jutsu development. For example, he could try to create a jutsu that has the same all - consuming effect as Galactus devouring a planet, but on a smaller scale within the ninja battles he faces.
It's very possible. In the realm of fanfiction, the sky's the limit. Writers love to mash up different concepts and characters. If Naruto were a Galactus fan, it might start with Naruto somehow learning about Galactus. Maybe he stumbles upon some ancient scrolls that mention Galactus' power. This could then lead to Naruto's journey to understand more about this cosmic being, and how it might relate to his own ninja world and his quest for power.
One interesting story could be where Galactus arrives in the Naruto universe and the ninjas initially mistake him for a new powerful demon. They try to fight him using their jutsu but soon realize his power is on a completely different level. Naruto, being the determined hero, tries to communicate with Galactus to understand his purpose and prevent him from consuming the world's energy.
Besides Naruto and Sasuke, Sakura could also be a main character in such fanfiction. Her medical ninjutsu skills might be needed to heal the wounded during the battles against Galactus. And there could be some original characters created specifically for the fanfiction who have some special knowledge or power related to Galactus and the Naruto world.
Well, it varies depending on the comic series. Sometimes, it's been a combined effort of multiple superheroes like the Fantastic Four and others. Each encounter has its own unique circumstances and outcomes.
Galactus' fate in the comics is complex. It's not straightforward to say who exactly killed him as it often involves multiple factors and characters coming into play. Different storylines present different scenarios.
Galactus was once a mortal named Galan in the pre - Big Bang universe of Taa. As the universe was about to end in a cataclysm, Galan entered a life - pod with some other survivors. But the pod entered a radiation - filled area near the Big Bang. Galan was transformed by this intense energy and became Galactus, a being with an insatiable hunger for planets to sustain his vast power.