Aren't most Brazilians mixed-blooded, with Portuguese ancestry? Of course today the country is a melting pot. But just as the Spanish conquistadores intermarried with the native Americans in the lands they settled in, so likewise did the Portuguese settlers.
He ought to have a latin appearance.
After all, all his paternal ancestry was portuguese back to king D.Afonso Henriques in the 12th century.
His mother and grand-mother were german, but his gr.grand-mother was the infamous Carlota Joaquina of Spain, another Latin, daughter of a spaniard and a parmesan princess, both of french origin, latin again.
What would be the difference between a portuguese, a spaniard or a italian, compared to a brazilian, based just on looks ?
He wasn't even particularly dark-haired or dark-skinned
Look at D.Duarte Nuno in 1930:
and the Count of Covadonga at the same age.
Would you say he looked brazilian too ? I guess it was just the fashion.
I give you an official portrait of the late Duke of Braganša where I cannot spot a trace of brazilianism.
And a very young DoB.
But I won't argue if you see D.Duarte Nuno with brazilian looks.
I can't. Neither physical and definitely not in temperament.
The whole picture you posted- D.Duarte and his brazilian wife D.Maria Francisca :
He had a very Latin appearance -- eerie, considering his international background and upbringing. Perhaps because he married a Brazilian: after all, a husband and wife who have been together for some time come to look like each other.
Found this photo on the wikipedia page -- https://en.wikipedia.org/wiki/File:Duarte_Nuno_de_Braganza.jpg
Come to think of it, the three children of King Alfonso II of Spain are also good examples of the effect of environment on physical appearance: they, too, were of mostly German ancestry -- undoubtedly underscored by their mother's Habsburg background (members of the Austrian imperial dynasty regularly married German royals). Yet, they looked very Spanish -- especially the second daughter.