The knight surveyed his chances. The undead hordes surrounding the castle had effectively bottled him in. The original hordes of Gaunts had been supplemented by a pack of ghouls that had followed the six-armed skeleton warrior. They feasted on such corpses as they found and howled bone-chilling dirges at the walls. The warrior who seemed to command this unholy mess seemed to be content to set up camp and wait them out.
Obviously, nothing would be gained by waiting - the fortress was on the frontier, and not garrisoned or provisioned to withstand a siege. The only option seemed to be to make a break for it when an opportune moment presented itself.
One of the players had made a character who was immensely strong and dumb as a post; essentially, he was designed to survive just about anything. That character and one of the others volunteered to test the Gaunts and see how powerful they were. They set up a diversion, where one volunteer lowered himself partially down the wall on one side. When the Gaunts swarmed to that side to attack the living thing there, the two PCs jumped down on the other to see if they could make short work of the bad guys. They were fairly effective against them, discovering that blunt weapons made short work of their bones. One of the Gaunts was that of a dead Ivinian viking; he bore a longspear. He got in one good shot to the unarmored face of the super-large PC and almost killed him in one blow! Everyone was far more leery of the Gaunts after that; they'd realized that I was going away from the cinematic style of play toward a "grittier" setting. In fact, it so impressed the players that they afterwards were very careful to design PCs to be effective outside of combat - a combat-oriented PC would have a short lifespan if he threw himself into battle in my setting.
Through attrition, they managed to winnow away some of the defenders and get rid of most of the ghouls. The six-armed skeleton warrior spent only three days at the castle, before leaving along with a small group of undead. The players decided it was time to attempt a breakout. During high noon, the player of the hunter character managed to sneak out of the castle while the others provided a diversion. He scouted out a portion of the woods to the west of the castle and was able to determine that the trail seemed to be free of major entanglements. He noted the presence of unusual-looking trees in the deeper woods; seemingly a breed of oak, their trunks were pitch black while their leaves looked pale. He noted a large number of skeletons of the larger animals under their boughs and decided they were a danger he did not have to face.
Over an additional day and a half, the PCs and the castle warriors managed to winnow down the under horde to a more reasonable number. They also managed to entice them to congregate on the side of the castle away from the gate. Then, the knight led the residents out of the castle towards potential safety in one of the garrisons.
Behind them, the ravening, mindless hordes continued to batter themselves against whatever was left, reducing hard-won prosperity into dust and ruin...