Before going deep, it is important to understand the early life and character of Galactus. Actually, Galactus is the sole survivor of universe which existed before the Big bang. In the pre-Big Bang universe, Galactus was a space explorer named Galan. He was a native of the planet Taa, one of the most advanced worlds in existence. The society of Taa were dismissive of the fact that their universe was dying and that all matter was converging on one position (the Big Crunch), collapsing into a new "Cosmic Egg", a sphere of disorganized, compact primordial matter. Galan discovered that the radiation pouring out from the Big Crunch was going to destroy everything in turn, and Taa's people were next.
Despite the efforts of Taa's greatest scientists, no cure could be found, and the population began to die off. Galan convinced the handful of remaining survivors to die gloriously by flying a starship into the blazing cosmic cauldron. The crew was killed as the ship entered the center of what was now becoming a "Cosmic Egg", where the next universe would be born. Galan survived and he was reborn as Galactus. One of the first Watchers witnesses his birth and forgoes the chance to destroy Galactus due to the Watcher's oath of inaction. Watchers are nothing but cosmic entities which observes the parallel timelines of the multiverse. In Hindu Sanatan Dharma, Maha Vishnu is one of the watchers who observe parallel timelines of the multiverse.
Actually, Galactus is not a villain, he is a cosmic balance, without him the universe will become in danger of being destroyed. He claims that one day, he will return much more to the universe than he has taken. By consuming the planets he is actually balancing the universe. Galactus is also considered as a force of nature.
Here we will see the shocking similarities between the Galactus and Lord Shiva. This may be just a matter of coincidence but according to me Marvel indulged the role of Shiva to the Marvel universe in the form of Galactus and the role of Galactus indicates us that how the cosmic entities like God and Celestials like Angels actually work in order to balance the existence of the multiverse.
Lord Shiva - The ultimate destroyer
First, let us clarify the meaning of the term – “celestials”. This term will be repeated again and again. Celestials are highly advanced species or god-like species. In Hindu Dharm, we refer them as Yakshis, Gandharvas, Angels, Asurs etc. We know that Lord Shiva is the ultimate destroyer of the universe. Shiva is represented as a Lingum. Shiva maintains the cosmic balance of the multiverse by destroying the universe so that the number of celestials remains limited. Now when the universe is created by Brahma new celestials are born. Shiva needs to destroy the other celestials to maintain the cosmic balance.
This is exactly Galactus does, he consumes the planets to maintain the count of celestials and to gain the energy which he uses for molecular restructuring or conversion of matter. Galactus and Shiva are the ultimate destroyers and both maintain the cosmic balance.
Shankar serves Shiva just like Silver Surfer serves Galactus :
We know that Shiva and Shankar are different from each other. Shiv is represented through the Shiv-linga, Shankar is always shown to have a subtle body/deity. It is all the praise of Shiv as ‘Param-atma’ or Supreme Soul while Shankar is praised as a Deity or divine soul.
In many scriptures, you will see that Lord Shankar is worshipping Lord Shiva. Actually, Lord Shankar serves the ultimate Shiva. Lord Shankar may be helping the ultimate Shiva in choosing the planets or even universe which needs to be destroyed in order to maintain the cosmic balance. The cosmic dance form of Shankar which is Natraj is to indicate Shiva to start the destruction of the targetted planet/universe.
Silver surfer exactly do the same thing. Silver surfer used to seek out new planets and worlds for Galactus. Silver surfer serves Galactus for his survival. No matter the targeted planets and worlds have any living species or not.