The female Fennos most notable physical aspect is their impressive size and girth. Their personality tends to be more morose than that of the males, but they are often prone to bursts of rage. They tend to be very confident, sometimes to the point of arrogance, but they also have a strong instinct to protect those smaller than themselves. In time past female Fennos had most positions of leadership and were a cultural majority. Even to this day, they are more present in the military. Thus, they tend to be very proud and hold themselves to high standards.

Male Fennos are smaller and lighter than their female counterparts. Their legs are proportionally much longer, as are their tails, making them excellent runners. Their speed is not only physical, but mental. Their minds work very fast, with male Fennos usually being smart and witty, but easily distractable, socially awkward and prone to rambling. They are in general more jittery than females and tend to be more self-conscious. However, they are not as easily irritable and tend to have a better sense of humor.