Sasarai10 wrote:Actually every character in Suikoden has a last name, but it's not mentioned. Even characters like Mina, Antonio and Sansuke have one.
That's simply not true. The official information states clearly that last names are a rarity reserved for nobles and people of great distinction. The vast majority of people in Suikoden's world have no last name. The exact system for gaining a last name varies by country but it is not particulary easy in any known nation and most people who don't have one by birth will never get one.
Freed has a last name by birth because someone of his ancestors did something to deserve it.
Humphrey was given his for his military service.
Percival got his when he was knighted.
On the flip side, plenty of commoners rise to high positions without gaining a last name, like Annabelle who was the leader of the City-States yet not granted a last name, and Lepant despite becoming the president of the Toran Republic did not get a last name.
It's even mentioned in-game in Suikogaiden how rare it is for Nash to have a last name that he has to lie about it to alleviate suspicion.
As for the topic at hand, if you've named yourself Emperor already you have all the authority you need to get a last name and it's unlikely that this family would not have one but much like the weird case of the name of the Governor of El-Eal it's never been revealed.