The Monster Wars was a period of protracted military campaigns and mercenary engagements (primarily subcontracted “venture parties”) organized by the nations of the old world to pacify/subdue/exterminate the dangerous beasts, supernatural monsters, and uncivilized races of their territory.
The kingdoms of the old world used to be a lot smaller and more numerous. Gnolls and orcs and crap were everywhere, and a noble could only lay claim to authority over the amount of land that they could protect from marauding wargs and crap.
So the King of Elswaine is first to bat, and he raises a huge army, declares he’s on a mission from the Cup Bearer to extend the grace of his protection over the rest of the world, and he starts steamrolling through territory, killing all monsters along the way. When he gets to the ruler of the duchy or whatever, he invites them to swear fealty so that they can unite and continue the crusade. And if the guy doesn’t swear fealty, well, the king of Elswaine has a giant army of veteran monster-killers just hanging out, and maybe he decides this guy is also a threat to the divine supremacy of human civilization.
The definition of “monster” is kind of vague, so there were a lot of isolated primitive human cultures that were exterminated, as well as stuff that would get the “animal” descriptor in 3.5. They killed a lot of wolfs and bears and crap. There’s probably going to be long-term ecological repercussions, but whatever.
- The beginning of the Monster Wars: the city-state of Elsewaine begin a crusade of killing monsters as a pretense to expand their territory.
- The orcs unite as one single great tribe.
- First dragon slain.
- Unification of Surejad: in the interests of more effectively fighting the orc menace, the powerful militaristic elements of the Menejadi melded with the mercantile and production skills of the Surese.
- Victory Over Eater-of-Chains: Eater-of-Chains was a fierce and unkillable horrible burrowing worm monster. The dwarfs had long believed it to be immortal, and too dangerous to deal with, and so had ceded territory in the interest of simply avoiding the damned thing. The human armies pieced its black heart with a silver lance, paralyzing it. It cannot be killed, and lies to this day, pinned to the ground by the lance, paralyzed. The black heart beats sluggishly to this day, and It stirs every so often in its slumber, seeking to free itself. A team of strong men with hammers stand ready to pound the lance back inside of the beast.
- Under the advisement of the prophetic Great Chief Grag Halfmind, the ogre tribes unilaterally surrender to human armies.
- A couple more dragons slain.
- Dragons form Treaty of Reprisal. First victims are the Renault household of Elswaine.
- Battle of Burning Black Fields: In Surejad, a massive joint Campagner/Elsewaine/Surejad army clashes with the Great Horde. The great warchief of the Horde sets the steppe behind his army aflame to dive them towards the enemy. This proves to be a real bad decision when the orcs are outmanuvered and rout. This is the last major military battle against the orcs, and their will is broken by the defeat. Most are cowed into submission.