[Butz]

In what little is written for an official backstory of Kingdoms, it mentions that the refugees from the original kingdoms fled the bomies and founded new kingdoms on the Archipelago. This means that the Archipelago is not the entire world, which means that there is leeway for other races from other lands that may not have been heard of by the cartographers of said Archipelago. Other than that, there is no canon backstory to encompass the entire world, so one person really can't bring up the claim that you're not allowed to use your imagination.

I certainly don't see a problem with Gryffon's character, as the racial difference merely seems to affect his character's personal values. Gryffon acts in a certain way and says certain things, because of the values of his culture.

It's really no different than two Humans, both raised in Human villages, except one was raised in a village of thieves, and therefore, acts radically different from the Human raised in a normal peaceful village. Though this difference isn't racial, they still have culture differences, and their actions have to be explained by the revelation of their past, just as how Gryffon's actions are explained through the revelation of his race. Two different ways to set a character apart from GENERIC RP CHARACTER A, but both just as valid.