You decide to not heed the requests of your people, they're already partying enough!
1216 AD, Late Autumn
"Duach?" You look at Aina with surprise.
As it turns out, the two have been getting along quite nicely, and your older sister seems to be enamored with the stately and handsome Duach, the elder of two of grand-uncle Deathans' sons. In fact, if what you just heard is right, the two have been eloping for afternoon walks and spend a lot of time in royal gardens, too.
You briefly consider
what kinda familial relationship that would be, for genealogy is hard. Their common full ancestor would be the Great Cyl himself, father of both Eirika and Yoe III.
But considering Ruberta's remarrying... half-uncle and half-niece?
"Isn't that incest?" Aina frowns at you mightily.
"Oh come on, we're further apart than cousins! We're not even of full blood relations, I've read the genealogy books. I love Duach, and I wish to be his wife! His soothing voice, his strong arms, oh, and his sparkly eyes. Truly, a man for me!" You roll your eyes. For as much as Aina seems to be wise and scholarly, it seems that nerdy girls do love hot jocks.
Wait, sorry for anachronisms - it seems that learned ladies do love handsome courtiers.
You decide to...
A) Play the stern, dissapproving father figure and remind her that she will marry for political gain, not for incestous love.
B) Shrug and let her to marry whom she wants to... but because you don't approve of this kinda kinship, she must give up her position as royal heir first.
C) Shrug and let her to marry whom she wants to.