Missed mini-boss, how to get businesw win (Sekiro: Shadows Die Twice)

I played sekira, and decided to take one mini-boss, a lonely shadow masanari, and so. I walked past him after the Palace the original is back, and its gone. The main question, if I missed the boss, and he disappeared, where can I get businesw, she was the last for his victory, tell me where businesw to take or is everything lost?