As for the historical Kirigakure, according to historical records, an Iga ninja called “Kirigakure Saizo” (believed to be an alias used by another man named Kirigakure Shikaemon) once attempted an assassination against Toyotomi Hideyoshi by thrusting a spear through the floor beneath him.

The attempt failed and Kirigakure’s life was spared on condition that he swore loyalty to the Toyotomi clan. In fact, there are some sources that suggest that Saizo was a “careless ninja” who was merely spying on Hideyoshi when he was caught.

And yet, as a result of getting caught, he ended up thwarting an actual assassination attempt on Hideyoshi by double agent Yusuke Takiguchi. This was the reason his life was spared on condition of declaring loyalty to Hideyoshi.