The grandmother could have killed them off for power at least the family members. She said she thought the alcohol killed her dad but he's too healthy so the grandmother could have poison him. The prince well royals kill each other all the time and it looks like his spirt power got sealed so he wasn't at his best in the 1st timeline.
Yay I know it's foul play. I was just pointing it out that it sounds unusual and comedic that everyone died young.
Spoiler
So the step grandma is power hungry. She wants total control of duchy. In order to do that she needs to get rid of any and all obstacles. She first got rid of the previous duke. She killed him I think by poisoning him. Then she killed the Duchess, Rubet’s mum. She made it seem like it was due giving birth to Rubet. She even had the doctor fake the cause of death. She did this because she’ll be able to have more control if the future Duke favours her, since the current Duke doesn’t really care about his stepmother. That’s why she raised Diego and Victor. If her own kids had the red hair it would have been better. Red hair and golden eyes are the symbol of the duke bloodline. She then poisoned the duke. Juliet noted that the Duke looks healthy, and doesn’t understand why he died if he’s not showing signs of illness, that’s because the poison that was used can only be effective if it’s consumed along with alcohol. Now the reason Rubet died in her first life, was not just because she was obese, it is obese related, but rather it’s because of the step grandmother. No matter what Rubet did, she could not lose weight, that’s because the step-grandmother used a special tea that cause Rubet to stay/gain more weight. Ig if she made it look like Rubet died because of her health, no one would suspect that it was actually her plan. She had already poisoned three people in the Duchy, it would be suspicious if too many people from the same died due poisoning.
Why comment spoiler under my comment when it was certainly a sarcastic question (which I clarified) and not a 'please answer me question'? Unwarranted opinions
I don't understand why every single character died early in her last life.