@corallsssssss not necessarily. According to some random Google article, apparently it isn't uncommon for Italians to have both their mother's maiden name and their father's last name. Although, the father's last name is the one used as their actual last name. However, instead of their maiden names, I just put my own spin on it, by basically giving them an American name and an Italian/ Spanish name.
So Reign's full name would be:
Reign Dior Alessia Dana Black- De Luca.
Ace:
Asa Rocco Atlas Axle White- De Santis.
I honestly don't know why there are so many As in Ace's name-
But yeah, I hope that explains it