Four Daughters of Armian - Vol. 1 Ch. 6

[MangaDex]

 

[Desireless]

I get that we're supposed to believe the little sister is oh so special, and born to be a ruler or whatnot, and this is somehow portrayed as if she is being usurped of her throne. However, I don't see a problem here, Re-manua gave them the option to choose, and they chose her as queen. She's also the oldest and has been brought up for the role, so to me it seems perfectly logical that she should be queen.