"Do you understand now?" One asked.
"Yes," Fran stared blankly into the night.
"Then, you will fulfil your end of the bargain,"
One began to descend as he has accomplished what he needed to accomplish. Though he never really thought of sparing Fran's life, having a spy that would penetrate deep within the enemy would speed up his inevitable victory.
Why? Information, of course! One has the opportunity to strike gold and shove it down the enemy's throats. They shall choke.
One had to be careful, and so, he needed to ensure Fran's survival. To ensure his survival, he needs to have something that would motivate him to do his duty, and that motivation is already there. His daughter and quite possibly his wife, if he has a wife at least. I mean, One does not know if his wife even loves him or if he loves her. If so, One only needed to protect the daughter if the wife was of no value whatsoever.
A good plan!