Humans

In Aar humans inhabit Nandaahr and Ahndaahr, the continent south of Nandaahr. Nandaahrs human population can be roughly seperated in 2 halves - the ones north of the dragonfang mountains and the ones south of them. 
Due to their short lifespan and their relative physical and magical weakness compared to the other races, humans have to make up for that with their inventive spirit and universal approach to magic with gives them the abbility to survive and adapt to many places. 

The two waves of settlers

The humans from the the north, especially the far north derive from the thirteen ships that arrived at the dawn of the second era in the area where you now find the city of Olim. They were tall, pale, blue eyed folks with bonde and red hair - this heritage is most alive in the far north of Nandaahr. Around the same time some colonists from Ahndaahr arrived at the southern shores. They first settled down in Masranur, formerly an old demon town, now quickly became the capital of the south. These colonists were a contrast to the northern humans - they had darker skin, varying from pitch black to olive with equally dark eyes and onyxblack hair. They bonded quite well with the demons and builded many more towns and cities. 
At some point both parties met. At first both didnt got along that well - and there are a lot of conflicts to this day - but in the end especially in the heartland both groups blended together over time.

Nandaahrs humans nowadays

Nandaahr hosts many different cultures, the heartland has some elvish influences, in the southeast the demons left their mark on the human culture. But in most parts of the continent cultures and ethnicities splitted up over time and formed many new cultures and religions. 

Magic

Human magic is completly different from the other races access to magic. Elvish magic protects and restores (eventhough they still have some firepower), demons magic is mostly summoning of undeads and other wicked creatures combined with other "dark" arts, orcs have their rituals and dwarfs their earthbound and alternating powers. 
Humans magic isnt that set in its ways. They lack the raw power of the other races, but humans can use the other races spells to a low degree while their own magic is more focused on the elements and destruction. It is more broad, yet not so powerful while the other races made it to perfection in their ways, but lacking the abbilities to use other magic.

Strenghts	Universal magic abbilities, high productivity, inventive  spirit
Weaknesses	short lifespan, vulnerability  to other races stronger magic
Continents	Nandaahr, Ahndaahr