To trace their background, then you cannot forget Japan's original culture for Vocaloid.
Vocaloid is surely produced by the human to dedicate the creation of the song and voice for Hatsune Miku who is the most famous digital vocalist with green hair as you know.
It is not talked about often but one of the most successful J-POP singers at present Kenshi Yonezu also has a similar background with his experience of Vocalo P called HACHI.
And when you look into their member organisation of YOASOBI, you will see they are configured with the singer Ikura and the composer at the same time producer Ayase.
So now, who is Ayase? Yes, Ayase is also one of Vocaloid producers abbreviated often as Vocalo P.
Their creation of music videos is always on the top topic because their animation dramatically describes existing Japanese novels. You can watch those creations on Youtube. Source: https://www.youtube.com/watch?v=x8VYWazR5mE (Ayase / YOASOBI)
Here are our collections of the piano score books / sheet music containing their songs! Try to get those in your hands and play their impressive piano accompanies! We also take up some titles including similar popular composers including Yorushika and HoneyWorks etc.