Epic siege at Shadeswords.
First of all, the artifact gold short sword was installed as a weapon trap at a junction of approach tunnels. I figured it was an ideal weapon for pounding on goblins, thieves, mounts, etc. that could inflict injuries without getting a kill that would jam the trap.
The goblins arrived in late spring right after the elven traders made it into a tunnel running to the Trade Depot. Four squads of cavalry (no flying mounts) and three squads of support monsters (cave crocodiles, giant cave spiders, more giant cave spiders.) To top things off one of the goblin squads was commanded by the goblin's law-giver and sole living civilization leader.
Three goblin melee squads streamed into an access tunnel from the north while the spiders and crocodiles came in from the east. A goblin crossbow squad loitered along towards an entrance and had little impact on the action.
The fortress garrison prepared for the defense by sending four squads of marksdwarves (5-6 dwarves each) to the fortifications of the fortress' "Kill Box". (The access tunnels junction and then enter a large open chamber from the north. This chamber is ditched to force attackers to run a zig-zag path to reach the fortress entrance at the south end. The south side had fortifications for the marksdwarves. On the west side is a fortification that a mine cart "cannon" can shoot loads of iron and silver weaponry. Plus the mandatory array of weapon and cage traps spotted along the route.) Dwarven melee squads are summoned a little later to rally by the gate and be ready to sortie if needed.
The two streams of attackers merge and start into the open area to be greeted by a storm of crossbow bolts from the waiting marksdwarves. Goblin cavalry mounts are also being taken out by traps as well. The numbers of the lead goblin squad thin out as they finish crossing the width of the chamber and start back on the "zag" side. Their leader gets wounded and they start to retreat. This causes the goblins to clump up a bit, slow down, and make a better target.
A shot from the mine cart gun cripples the lead elements of the second squad and also pushes a number of wounded goblins and mounts into a ditch. The second goblin squad starts to retreat as well. The tunnel exits are sealed at this point to keep the goblins in. This also locks out most of the goblin crossbow squad.
The support monsters are taking the lead now - sixteen giant cave spiders and eight cave crocodiles. Traps and bolts are taking a toll, but they are advancing further and further along the path. A shot from the mine cart gun kills a few, but they keep coming.
At this point a marksdwarf wanders out the gate and starts advancing down the zig-zag path towards the goblins. He stops to fires a few bolts, but appears to run out and intends to enter melee combat with his copper crossbow. He draws the attention of the remaining few giant cave spiders as they start tossing webs across the chamber and make transit a bit sticky.
The marksdwarves are running low on bolts, so they are given orders to withdraw from the fortifications and reload their quivers. Melee squads are deployed out the gate to take on the weakened goblin force head-on. (At this point the spiders are dead, as well as the few crossbow goblins that got in.) The line of melee dwarves meets the line of goblins and mounts right when the marksdwarf meets the goblins as well. On the way an axe lord gets entangled in a giant spider web and triggers a weapon trap; leading to multiple injuries and the axe lord being disabled and unable to stand as he gets pummeled by iron spiked balls.
The marksdwarf in melee does fairly well. He causes a elite axe goblin to dodge into a ditch, and then single-handedly kills a giant toad with consecutive hits to both rear legs and then a fatal crushing skull blow. The regular melee dwarves then pass him and proceed to start carving up the goblins with sword, spear, and axe. The goblins have scattered back into the closed access tunnels and the fight rapidly becomes squads of dwarves fighting in the various tunnels with the remaining goblin stragglers.
The goblin law-giver is found in a side tunnel suffering from a crossbow bolt wound and finished off.
The civilian population of the fortress is set to hauling bodies and pieces of bodies to the dump before they rot. After that they have heaps of armor, weaponry, and clothing to haul off. The wounded axe lord is carted off to the hospital for a multi-month stay that will include five splints being applied before he can leave.
Fifty goblins and mounts were killed, so a nice harvest of goblinite was had. The weapon trap with the gold short sword did quite well in it's mission to inflict multiple wounding attacks without getting jammed by a kill. Lots of bruises, but also a number of broken bones and torn ligaments inflicted as well.