I just realized... Aurelion Sol has helped us realize who Nagakaborous is.
So Illaoi worships Nagakaborous. Nagakaborous is a sea monster god with tentacles, right? But then she says it's about "motion." However, Aurelion Sol comes by. He be like, "You do not understand your god, Illaoi."
So what does that leave us with? Nothing so far.
BUT WAIT.
Through my scientific/religious studies research, I have been able to narrow down what Illaoi's god truly is. Aurelion Sol knows it, and I have figured it out! Nagakaborous is, in actuality...
https://d.ibtimes.co.uk/en/full/1373539/church-flying-spaghetti-monster.jpg
That's correct. It makes sense now. Nagakaborous believes in uniting the people of this world under his watchful tentacles, which are made of salty water. Salty water is used to boil pasta. Thus, we must refer back to the sacrifice of the Flying Spaghetti Monster.
https://i.ytimg.com/vi/X-_ZBEScuzc/maxresdefault.jpg
It all makes sense now! THANK YOU AURELION SOL!