In Episode 18 when Go Geon asked her if it was her sword that struck his father last I remembered something from yesterday's episode and I actually think that the village chief from ghost valley struck him last for good measure even though it wasn't shown.
Dal's mother holding onto Go Geon's legs to stop him from going to kill Dal and Ga Jin was honestly one of the saddest but strongest moments I've ever seen in a kdrama. She gave her life while being not able to defend herself just to save them
I just realized Bi Soo's last name is Han and the Han's never get the girl. Bong Hwan from Mr. Queen cursed all the Han's but only 3 generations so perhaps the curse has been broken now