I'm glad she doesn't act like a damsel in distress, desperate for him to save her in this modern Joseon. She no longer calls him 'husband' and refuses to be used by him. I can see later she makes her own money and becomes a fashion designer starting with her fashionista half-brother-in-law.
I thought because she tried to save him in the water at the first time. She touched his tattoo and pulled his hand to save him but he's unconscious and too heavy. She said "I have to let go if I want to live" then the tattoo got transferred. But as a demon with superpower, why is he unconscious? I think he lost his superpower and the deity chose her to become the 'savior' now for a period of time. Although she couldn't pull him out of the water, the next scene they were both safe out of the water.
So apparently it looks like grandma might just be responsible for DDH's parent's death.The entire parking place…
I'm not sure which one you meant but for me the culprit in the family is Joo Seok Hoon, the one who rides with her, since he's also a main character in the cast list.