The Existence of Humans[]
Back when The Greatest Four found the Material Plane, humans were already there. Although legend says they had a very advanced society, when history was destroyed, none of it seems to have stayed with them, and no one knows much about what they could have been like before then. Humans had a special trait, something unique, that drew the attention of The Greatest Four to their world. As such, when the second races were made, they were made in the form of humans, and called Humanity as well. This is why many of the creatures in the world seem so similar to humans, as many gods have tried to create beings in the shape of humans, not exact copies, but trying to make them better in some way. While most other races will of course say they succeeded in becoming better than humans in something, no one can truly say if they are better in the end. Many humans believe they are better or more privileged than any other race because they were the first beings. This, while certainly not a defining factor of how humans act, is so abundant that it is the stereotype of humanity-- A distinct belief of superiority.
Humans and Divinity[]
That trait, that special something that humans seem to have, is often called the Unique Divinity by other races who study them. They are gifted with limitless adaptability, and a strange connection to the Distant Gods that so many races wish for. Many humans who become religious enough to be granted magic are often capable of simply asking to be stronger in dire situations. Humans appear to have some tiny piece of godhood in each of them, which grants them power and capability. None of the other races have this, and it is yet another reason why many humans lord themselves over others.
Divine magic to humans is often more than just a tool to serve their deity. The clerics with the most powerful spells are often celebrities among their church and the civilians around them, as it is seen as a larger connection to godhood. All one step closer to the beings the worship. Those who draw the most power as spells must be the closest to gods on earth, in the eyes of humanity. Some clerics serve in order to gain this fame. Ironically, there are several gods who are perfectly fine with that, such as Haage, the god of Greed.
Relations with Other Races[]
As a whole, humans are raised with the knowledge that they were the first in existence. They are born with a sort of majesty in knowing this, though many turn it into a feeling of compassion for others, knowing they can help many with their gifts. The stereotype, however, is that humans are all pompous about this knowledge, treating any other race as a sort of pitied room mate, acting like they are only sharing this world because they are so high above them that they pity those without their divine gift. There are also humans who think they are ultimately better than all other races, and can not ever be overcome or even touched by those who lack their divine connection. These, however, are (hopefully) very rare.