Guerrilla Warfare Is as Old as Mankind
Guerrilla warfare is as old as mankind. Conventional warfare is, by contrast, a relatively recent invention…. The first genuine armies—commanded by a strict hierarchy, composed of trained soldiers, disciplined with threats of punishment, divided into different specialties (spearmen, bowmen, charioteers, engineers), deployed in formations, supported by a logistics service—arose after 3100 [B.C.E.] in Egypt and Mesopotamia….
Considering that Homo sapiens has been roaming the earth for at least [150,000] years and his hominid ancestors for millions of years before that, the era of conventional conflict is the blink of an eye in historical terms….
Throughout most of our species’ long and bloody slog, both before the development of urban civilization and since, warfare has been carried out primarily by bands of loosely organized, ill-disciplined, lightly armed volunteers who disdain open battle. They prefer to employ stealth, surprise, and rapid movement to harass, ambush, massacre, and terrorize their enemies while trying to minimize their own casualties through rapid retreat when confronted by equal or stronger forces. These are the primary features both of modern guerrilla warfare and of primitive, prestate warfare whose origins are lost in the mists of prehistoric time…. Guerrillas therefore may be said to engage in the world’s second-oldest profession, behind only hunting, which draws on the same skill set.
— Max Boot, Invisible Armies, pp. 9-10
How about hobgoblins and orcs fighting like this?