- "The most common race. Includes members of the winged as well."
- — LuCT PSP description
The most common race found throughout the whole game series.
Ethnicies vary depending on the location of the story, and they are one of the main factors behind the Heim Conflict during Tactics Ogre: Let Us Cling Together. Some examples of varied clans and tribes are the Bakram, Xenobian, Lodissian, Walister, and Galgastani.
Some of the most powerful and respected people in history are or were humans, ranging from the Dark Sage Rashidi and the once kind but corrupted Empress Endora, to the White King Tristan Xenobia, the Deva Quass Debonair and the revoloutionaries Denam Morne and Destin Faroda. To date, all protagonists in the series have been humans.
For gameplay purposes the Winged Folk are considered a variation of humans. This means that skills that affect humans (Anatomy and Recruit) can be used on the winged as well.
As mentioned, player armies will often contain an overwhelming majority of humans. This is because of two reasons:
First, humans are the "default" race found in the games, and the easiest to recruit, under the "Hire" option in shops. You'll usually have to go on your own to find and successfully recruit other races.
Second, almost all generic classes are available to human units, barring a very small amount of race-exclusive classes that are often a variation of regular classes (ex: Matriarch being an advanced Wizard). If a non-human class has access to a generic class, it will often differ in terrain movement and base stats alone, or very rarely a racial skill, but the difference will remain minimal.
Not to mention, humans have the widest class options in the series. Non-human units, including humanoids, tend to be limited to six or so classes compared to the 20+ options available to humans.
So, while there may be reasons not to use a non-human unit, there's truly no reason not to use human units, and in some games in the series it's even imposed.