I always imagined that there were two Spains (in Hetalia terms):
"Spain" - Represents Isabelline, Alfonsine and Republican Spain (as well as modern day Spain)
"Nationalist Spain" - Represents the "old" Spain, including the Carlists and the Fascists. This was the Spain that did all the terrible things to the Latin American colonies. He's "Spain's" older brother.
Hmm...you know what, I might do a profile for my idea of Hetalia Spain. >