The story has a child protagonist (or starts off as a child protagonist for a significant portion) in a position of aristocratic authority in fantasy/isekai. The child protagonist may also attain aristocratic authority (influence, political power) later in the story. Includes Aristocracy/Nobility, Villainess/Villain, Duke/Duchess, Age Progression, Time Progression, Passage of Time.
Note: this list excludes protagonists that are Royalty or Imperial Family (Prince, Princess, etc)(refer below).
A protagonist with aristocratic authority in Fantasy/Isekai here
Protagonist is a Servant, Royalty, or a Saintess/Saint in Fantasy/Isekai here
Protagonist was thrown into a Novel/Book world here (Female Protagonist) here (Male Protagonist)