Saint-Domingue is Haiti, Santo Domingo is the Dominican Republic.
I don't own Hetalia! end/AN/
"One, two, three, four, five." Santo Domingo's brown fingers tapped each fingertip of Saint-Domingue's open hand. "That's five, Ayiti. There were five."
Saint-Domingue stuck his dark fingers into his mouth. France described him as 'darker than tar,' a comparison that had made Saint-Domingue scrub at his skin to see if it would come off, become the lighter color on the palms of his hands and the soles of his feet. It did not. "Five?"
"Yes, there were five," Santo Domingo said, quite pleased with this game. He was the bigger child, and he pulled Saint-Domingue's fingers out of his mouth, spreading them again so he could count again. "One, two, three, four, five, just like your fingers, Ayiti."
Saint-Domingue smiled, counting along his finger. "One, two, three, four, five."
"One, Jaragua, two, Marién, three, Maguana, four, Maguá, and five, Higüey."
The names delighted Saint-Domingue. He loved this game, the way the sounds of the names rolled off of Santo Domingo's tongue.
"Then, España came, and boom! They all fell down!"
"All fell down! Espagne!" Saint-Domingue said with a grin. He had never seen Spain, having been created when France took part of the island. Hispaniola, the island he and his brother, Santo Domingo, shared together.
"You know why. They were coughing! They had marks all over their bodies! Down, down, down, fell to the ground." Santo Domingo spread his hands wide. "That's why we don't see them now today!"
"Santo Domingo-" Saint-Domingue started, but that was when his brother switched to frowning.
"Kiskeya. You call me Kiskeya, Ayiti!" He shoved Saint-Domingue, making him fall down onto his back. Then he stood, saying, "I'm gonna go back home. You go back to France."
"But Sa- Kiskeya! I wanna stay with you!" Saint-Domingue pleaded.
"Adios." And Santo Domingo ran out of their clearing for home.
/AN/In the 1500s, Spain colonized Hispaniola, one of the first places discovered by Columbus. However, they couldn't control the piracy, and in the 1600s, France managed to get a colony on the west side. So, the colonies were called Santo Domingo and Saint-Domingue respectively.
What the two are talking about is the native population, or the Taino or Arawak. The worst case of depopulation was in Hispaniola, through a combination of disease, slavery, and other things; the native peoples were declared 'extinct' by experts of the time, though it seems the Arawak blood still runs in many Haitian and Dominican veins.
Kiskeya and Ayiti are both Native names for the island of Hispaniola. Also, in my characterization, I figure the Dominican Republic is both older and knows more about their past due to having been around longer.
Hope y'all enjoyed it! I hope to update it tomorrow.