The teal haired girl is Odileia, an android, or an automata, that was built from alchemy. She is the librarian of the "No. 2 Library," and aids Ayesha by granting her access to some of the collections of the library. Though monotone and expressionless in the beginning, as Odileia interacts with Ayesha she seems to gain humanity. As the librarian, she seemed to have knowledge on every writing the "No. 2 Library" contains, but lately her memories seem to be rather unstable.
The browned haired man is Kayle Tarenbert. He is the owner of a bar, "The White Crow", in the city Hornheim. As a skilled merchant, he managed to start his own bar alone at a young age, and is known for handling information and rumors from all over the world. Ayesha seems to frequently visit "The White Crow." Though he is the barkeeper, apparently he can't drink alcohol.
Finally, the black haired girl is Tanya Folta. Living in a far off land with her family, they make a living from digging and selling salt. Although still only 11 years old, she works hard hoping to one day travel to the outside world. Tanya and Ayesha meet when Ayesha is on a quest for a certain flower.
Check the links below for more details (like the character's blood type, age, and height) and pictures.