Some characters may be excited. They might enjoy seeing their world expanded in new ways. For example, a side character could be happy to see themselves getting more spotlight in the fanfiction.
They could be shocked. If the fanfic takes a really unexpected turn, like making a villain into a hero suddenly, the characters might be taken aback. It's like seeing a completely different version of their world.
If parents come across disturbing content in Descendants fanfiction, they should immediately stop watching it. They can also report the content to the platform where they found it if possible.
Inosuke doesn't become a Hashira in the manga. The story progresses with him having other significant experiences and achievements instead of achieving that specific position.
It's hard to give an exact number. Different story arcs and battles led to the deaths of multiple hashira. Some died heroically, while others met their fate in unexpected ways. The count changes as the manga progresses.