Maybe it has some really rare adaptations. For instance, it could have a special organ that gives it an advantage in its ecosystem that we don't see in other frogs, making it seem like something out of a strange fictional story.
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.
Definitely not. Genya remains outside the ranks of Hashira throughout the manga. This is because of a combination of factors such as his skills, experiences, and the overall direction of the story.
It could mean that the kagaya frog has some really unusual or unexpected characteristics. Maybe it has a very strange appearance, behavior or habitat that is more out - of - the - ordinary than things we typically find in fictional stories.
Perhaps it's a form of resistance or remembrance within the context of the novel. If the story is set in a situation where some characters have been oppressed or silenced, saying their names is a way to assert their existence and significance. It might also be related to a ritual or a cultural aspect in the fictional world of the novel.