Ships inside the book; -Muzkoku(main) -slight DouKoku(Douma is the Top) -slight Akakoku(Akaza is the top) -Doukoto -Akayuki -slight Kaidaki -slight Gyokido(Gyokko x Sekido) -Slight Muzan x Yoriichi(Muzan is the top) Explanation:This Story is about Kokushibo Who Had a Job to get the blue spider lily but Muzan wanted to have fun with him for a bit, This book is called Dark River Flow because it mean that It's an endless River that won't be reached.