Kagurabachi — Just the Two of Us

A flashback from Chapter 2 recalls the only things Chihiro and Shiba knew at the time about the Hishaku were that they were a small, elite group of sorcerers and that they changed their method of operation starting from four years ago. After Chihiro's meeting with the Kamunabi in Chapter 46 , Hiyuki had informed him they began their most devastating moves from three years ago, with Kunishige and Misaka's murders, but when the Kamunabi began mobilising the Hishaku ceased activity. Despite the Kamunabi's efforts to gather information, they still did not know much about the Hishaku, which was the reason they were constantly on the back foot.