Hummm i have this gut feeling that the human King/former hero might be her husband. That would explain the weird feelings i get when i see him go see her.
Guess i was wrong with what was explained in the next chapter.
I was hoping demon mama was just being tsundere and the chapter would end with everyone finding her secretly doting on her grandchildren. Though I guess this development is interesting too!
Ok, that moment when the king said he couldn't let Dernier escape had me thinking he loved her
So with this new info it feels like less of a stretch
Theory:
Shinichiro > comes to this world and makes baby with Dernier > ends up becoming a hero for the 'human side' > and then capturing Dernier to still keep her close
The Gramps, back in their heydays, is a lolicon and was caught flirting to a random loli in the park.
Grandma called the FBI and soon she chased gramps to smack him in the face.
Too bad, the hero caught her...