1st world:
The demon that spits fire is the very first nika of destruction. Hence why he was able to create the power of the SUN in his hands. This individual most likely was the most powerful hybrid LUNARIAN that was also a merman that was exiled from the other races based on his belief system. This indivual probably had access to the anceint weapons. The serpent in this analogy is an individual whom had the powers of the sea that was able to gain its power from the moon (poisedon).
This draws empahses as to why it was being praised and offered sacrifies /gifts by the King whom represents world leaders, the angels whom represent the different tribes of skypians, and animals whom represent the mink tribe. They gazed upon the moon since all of those races are affiliated with it. Making sacrificess to gain protection . It was almost like they were making wishes on a star (hence the star reference)
The individual whom we know as the one true nika fought the actual nika for the power of the sun. However nika needed the assistance of all races including the giants and ancient giants, good lunarians. Skypians, samurais, minks, Fishmen, the mermaid princess, ancient robots and vivis ancestor etc
They won the first war and defeated imprisoned / sealed the nika of destruction whom was now EARTH BOUND.The individual whom we know as nika of laughter gained the powers of the nika of destruction (the demon of flames). Upon gaining said powers, the new nika laughter (whom is good) granted the desires of the different races that helped him in the form of powerful fruits through the use of sharing his fruits ability of imagination into the first Adam tree. This is how devil fruits were first created. These fruits were the forbidden flame that was overtaken by evil desires of living creatures. Upon making this grave error the nika of laughter "now with the title of sun god" wanted to rectify his mistake. However the former nika of destruction who is now considered the diety of earth was enraged because he was enslaved. Together with the serpent of hell flame (someone with blackbeards fruit) assisted the nika of destruction and they fought the 1st nika of laughter.
The 2nd world
Now that the nika of destruction had returned with the help of darkness they fought the nika of laughter. The nika of laughter in retaliation granted more fruits to those whom wanted power to fight the nika of destruction. The diety of the forest which is the first Adam tree that created the devil fruits with the nika of laughters authority, created more demons (Devil fruit users) to aid the nika of laughter. The sun god nika did nothing but spread the seeds of power and war for the defeat of the nika of destruction. However this angered the nika of laughter's allies. They saw him as becoming something worse than the nika of destruction. So instead of slaying the original nika of destruction they instead slayed the nika of laughter "the sun god" based on what he was becoming. It was then revealed that this was the doing of the nika of destruction and the serpent of dark flames whom tricked the nika of laughters allies into not believing him
Upon understand this the minks saw a vision of what negative affects this would have. There would be separation of all allies aligned with the nika of laughter. The nika of destruction would grow and reclaim his authority slowly. Putting doubt in the hearts of many. He would enslave all races that assisted the nika of laughter. The nika of destructions descendants would be known as the celestial dragons.
Angered by these events poisedon cursed the waters and seas to limit the destruction of what was created with devil fruits
The 3rd war
The voice of poisedon in the void century cries out to those whom relied on the power of the moon to reincarnate the the sungod into the very vessel that he had created ; a devil fruit. Even though the power of the nika of laughter is needed his children (Devil fruit users) will still be cursed by the sea because of the nika of laughter. If both the nika of laughter and poisedon were to meet in would the destruction of the world (rectifying the mistake of the nika of laughter and defeating the nika of deatruction).
This could also explain why the nika of destructions descendants "the celestial dragons believe od themselves as gods, why the lunarian are also tied in as the true gods and why the celestial dragons wear bubbles over their head the same way people do if they go to Fishman island. And why there are alot of dragon reference with both fiahmen and celestial dragons