Muzan dismissed Duma and went to a secret room only known to him.
In this room there is a painting representing him with Giyuu in fox spirit.
Nothing when looking at this painting he remembered the happy days they spent together.
Giyuu was unaware of his true nature and that was fine.
Unfortunately one day two slayers tried to kill me and I killed them immediately without knowing that my beloved had seen me.
As soon as he saw Muzan tried to convince Giyuu to stay with him but the kitsune backed away in fear whenever Muzan approached.
And Giyuu's steps end up in a cliff and he fell.
Muzan had no time to save him and Giyuu died.
500 years since that tragic day and Muzan had sworn to find his kitsune at all costs.
To be continued