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.
One highly regarded fanfiction might be the one titled 'A Moment of Tenderness' which beautifully depicts the relationship between Inuyasha and Sango leading up to their first kiss. It has great character development and the build - up to the kiss is very well - written.
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.