I haven't played yet, but I am wondering if MC is the 4th child why there is no comments about the 3rd child on this page? is it part of the plot?
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The MC is 4th in line, but the 3rd child in their immediate family. There is a cousin that comes before the MC in inheriting the throne.
Inheriting goes eldest to youngest:
Alberich (brother)<< Sieghardt (brother)<< Eirik (cousin)<< MC (youngest sibling)
It’s explain in more detail in the game. Hope that helps.