Kaoruko is fascinating. She is focused on a single purpose and driven to a state even she thinks is wrong. Her gentle manipulation didn’t feel evil but perhaps it was. It seems the abuse Minamoto-kun got in school was partly her fault. Maybe she messed up his life, maybe she saved him from something worse.
After achieving the goal she dedicated half her life to, what will she do next? I think the story hinted that she might continue to send lovers his way. I think this is where she must really decide whether to free him. In the end, the main feeling I’m left with is curiosity.