Inuyasha was a Japanese manga series created by Rumiko Takahashi and started in 1993. The story was about Inuyasha and the other characters searching for the Jade of Four Souls. The work was deeply loved by Japanese anime lovers and was translated into many languages and popular all over the world.
It's quite close. The anime of Inuyasha largely adheres to the manga, with only a few minor differences that don't significantly impact the main plot or characters.
I'm not sure which specific novel you're referring to. Different novels have different important chapters depending on the plot, characters, and themes. For example, in a mystery novel, the chapter where the big clue is revealed could be a very important 'capitulos da novel'.
The Inuyasha manga ends with a resolution of the main conflicts and a sense of closure for the characters. Inuyasha and Kagome's relationship reaches a fulfilling point, and the threats they faced are overcome.
Well, in the end of the Inuyasha manga, the conflicts were resolved, and the characters found their peace and happiness. It tied up most of the loose ends and gave a satisfying conclusion to the story.