Sergeir has long black hair combined with a sparse beard of the same color, vibrant orange eyes and dark skin. Being a beorning, also has three blood red stripes painted on his face. The bear form follows the same pattern as his hair and beard, being a black bear. On hot days he keeps the voluminous hair tied back in a ponytail, when not hiding behind hoods or masks while selling his goods.

Sergeir will always be seen wearing relatively comfortable clothes with lots of pockets and carrying several bags, the life of a traveler requires him to be able to carry as many things as possible. Among those things: coins, cooking ingredients, honey cakes, and a variety of things he bartered for on business trips.

In general, has a large stature and is quite tall, even for a beorning. One of his most comical problems is when he visits hobbit houses and always ends up hitting his head on the ceiling. At first glance Sergeir can have a threatening appearance, especially when is completely covered in clothes and with a set of hood and mask, leaving only his eyes visible.