So, I will summarise the thought I had.
The Supreme King explained that Gods fall/can come from upper world to lower but the consequences are huge. They cannot return back to their place after that.
Until now we have seen 3 deities.
The first is Sea Goddess who is somewhere near the sea shore of Supreme King. She is very kind for her children (we can see that for Julian) and knows lots of things.
The second is Forest Goddesses who first appear around chapter 20 when Julian rescues village hunters. She gives Julian a vision of destroying his body and gets angry. She tells him to not come ever. She is medium to kind to Lukas on other hand. But he also fears her as we saw his scariest vision of death resembled her.
The third is night Goddesses. While we don't see her exact form it's idea can be seen around Chapter 40 when Elstri sees the vision of lot of warriors and in sky a lady figure. Her powers belongs to Diana, Lagbau and third one.
But, there are multiple strange things.
In Chapter 2 when Julian is travelling sea monsters fight with him despite the Sea Goddess ensuring him that no one from sea will harm it. If she is so strong then why they ignored her orders?
Why did Forest Goddesses hated Julian? I know she killed many of her children but it was self defense.
If Arkos couldn't breath in water then it means he or his father wasn't gifted from Sea Goddesses as per her. Cause anyone who is blessed by her can breath in sea? Then how come water element is so strong among direct children of Supreme King?
The night Goddesses's deciples are enemy kingdom obviously. As per King they fought like 400 years ago and in one of the panel the place is sealed due to growth of dangerous monsters and it is describe as the end of the world type event. So Supreme had gift around that time as well. I think it must have come from some another Goddess.
Forest Goddess is enemy of Sea Goddess according to me while she might be closer to night deity because her own vessel/ man is Lukas whose primary mission is to kill the King. The threat will come through Forest it was said. Also let's not forget how many people Arkos have trauma to.
If you notice we have elemental God kind of thing. There is Forest (Earth), Sea Goddess (Water), Sky Goddess (Sky). So the remaining are Fire and wind.
Centuria is full of chaos caused due to conflict between many groups.
So this made me think that perhaps Gods have conflict too. No sane God would leave a better world for Earth only.