Nikas entire idea was introduced to the story merely chapters before it was important. That’s one of the worst ways to introduce something that’s supposed to be a major plot.
So the idea that this god of freedom isn’t known in Skypeia where ancient religion was a focal point. Wasn’t rumored in Impel Down the worst prison in the world. Wasnt even mentioned through a Poneglyph.
The lore of Nika was so horribly forced into the manga that it legit feels like it’s something oda didn’t even think of till very recently.
So the idea that this god of freedom isn’t known in Skypeia where ancient religion was a focal point. Wasn’t rumored in Impel Down the worst prison in the world. Wasnt even mentioned through a Poneglyph.
The lore of Nika was so horribly forced into the manga that it legit feels like it’s something oda didn’t even think of till very recently.
But as you said, it's odd not having that being mentioned even once before