Professionals like this certainly didn't fight to the death, or even to serious maiming, since many of them stayed on the circuit for years. The quarrel in street A nd then, there's the street brawl. Then, as now, gangs of armed young men roamed the streets of the major cities of Europe. No rules apply here, and there's more than one reason why a nobleman never went anywhere alone or unarmed. It is was part of the social role to be attended by servants and hangers-on, and they came in handy in a tough spot.
T here is also the grey zone of the professional duellist.
This person is an assassin for all intents and purposes. There isn't much information about this type of person, but there are hints that case, for example, was an assassin's favored weapon form. Warfare in the sixteenth century is in a state of transition. The development of gunpowder technology means that a typical army has infantry carrying pikes and arquebuses, heavy cavalry armed with the 18 foot lance, light cavalry armed with wheelock pistols, and an artillery train of cannon and the specialists who tended it. For all of these soldiers, the sword is a secondary arm.