Master Dufner:
Hahaha! No, Giran is not entirely populated by lazy, fat merchants! I admit, we do have our share of those, but we also have many a hyper and studious merchant. Not to mention loads of highly trained guards and sentinels. Someone has to protect all that merchandise! Hahaha!
Most of the mercenaries are hired by the Merchant Guild Association and are highly trained members of this Warrior Guild. They're as skilled of fighters as you're likely to ever encounter in your travels.