My friend, it marked Keiko's comeback to the scene. She appeared from the dark, standing from the top of the scene in her beautiful outfit.
I think the anime also combined both... IIRC hue.I just want to add that at the concert they sang "the main theme of Kimetsu no yaiba" and "to destroy the evil." At the concert I thought it was a single song, maybe it was a special arrangement ....
Shiina is composing Film score which every scene has a unique music made for it and he did about 600 track for the whole show so no surprise their is a lot of instruments.No Kajiura news sadly but,
Go Shiina made a new insert song for the last episode with Nami Nakagawa, and it will be released on the 30th of August.
Commercial (Digital) published by Aniplex, Aniplex Inc. on Aug 30, 2019 containing vocal from Demon Slayer: Kimetsu no Yaiba with compositions by Go Shiina performed by Nami Nakagawavgmdb.net
Edit: his soundtrack details are also updated, and I’m wondering why and how is it necessary to use so many instruments to produce in the end only a random soundtrack.
Commercial, Enclosure (CD) published by Aniplex on Aug 28, 2019 containing original soundtrack from Demon Slayer: Kimetsu no Yaiba with compositions by Go Shiina performed by Go Shiina, Manabe Strings (Yu Manabe, Tomomi Tokunaga, Masahiko Todo, Naoko Ishibashi, Yuya Yanagihara, Ayaka Notomi...vgmdb.net