Well, it can be considered popular. It has a certain following. The world - building in 'ragna crimson light novel' is really appealing, which is one of the reasons for its popularity. Also, the character development is engaging, making readers want to keep reading to see how the characters grow and change throughout the story.
Yes, there might be. Fanfiction platforms are filled with all kinds of creative crossovers. You can start by checking major fanfiction websites like Archive of Our Own or FanFiction.net. Just search for the keywords 'Naruto' and 'Ragna the Bloodedge' in their search bars, and you may find some interesting stories that combine these two characters in unique ways.
Eliza develops by becoming more confident. At first, she may be shy or reserved, but as her webcomic gains popularity, she starts to come out of her shell.
I don't know exactly who this Eliza is. There are so many authors in the world. She could be a self - published author or one who is known in a particular region or genre.