Everyone player has the permission to control 3 additional minor characters- NPC's as we call them - in addition to his/her main character. You can have more if you justify it by something (like family of the character.)
The NPC can be your character's bodyguard, apprentice, friend, wife, husband, child, parent, etc.
The NPC has to belong to a race, and can also optionally belong to a class, but he/she should not be more detailed that the main character.
If you justify it well, your NPC can belong to a non-playable race as well, for example. demon, angel, fairy, kobold, genie, centaur, pegataur, or even a non-humanoid creature (unicorn, pegasus, pegacorn, phoenix),or a normal animal too (dog, cat, horse, fox, wolf, bear, lion, tiger, cattle, pig, sheep, goat, etc.).