A One-Round Living Greyhawk Ratik "Mini" Regional Adventure
From the introduction:
The bounty on orc and gnoll scalps in the Loftwood has attracted a diverse group of people seeking fortune in hunting the humanoids; Mercenaries, hunters, rogue militia and army soldiers, and adventurers. But now an unlikely visitor, a diplomat from Marner wants to venture into the woods and contact the mysterious "invisible army" that seems to be helping Ratik in the fight against the monstrous humanoids of Loftwood.
Part two of the Loftwood trilogy.