Read it official: VIZ or MANGA Plus. Chapter 47 opens Sword Bearer Assassination. A Sanso is attacked. Uruha is the prodigy loyal to the Rokuhira name, the man who mastered Iai White Purity by sixteen, the bearer who loses the will to live when he hears Kunishige is dead and then meets the son. Kumeyuri is his steel. Natsuki was a candidate. Uruha was chosen.
Why the title is a person
The auction spoke in architecture. The long book speaks in names: Uruha, Samura, Iori, Natsuki, Kiri. Chapter 47 is the first of those name-titles. The train, Hiruhiko, Kokugoku, and Senkutsuji are the commute this issue starts. File: Uruha. Blade: Kumeyuri. Arc: Sword Bearer Assassination.