They aren't siblings but her mom has connection to Yayul's life later. As for the mom, I'm not sure, I also wonder if she's alive(￣∇￣")...but she is definitely in the other side...the darkside
Was this the reason MC’s father was poisoned? Because he got her mom pregnant? I mean he’s not the most important figure in the martial world so why was he singled out right?
No. It's the exact opposite. Her dad is well known and very highly respected. I don't want to give spoilers so I'll stop here.
What happened to her mom? Kind of hoping her mom is Yayul's mom and they're actual siblings or something.