the most fun yet has come...
during the summer of 1283(year 3-4), CherishedShades was sieged by a force of darkness of 48 goblins all mounted on war giant olms, with an additional squad of 8 giant olms and lead by 2 spearmasters and 1 pikemaster. In the same summer, shortly after the goblins arrived a expeditionary force of 60-80 undead arrived, and the goblins fought and killed the undead that spawned on their side of the map, taking minimal casualties. Then a second undead force of at least 140 undead, maybe as many as 180 showed up and fought the goblins in a bloody battle that destroyed at least one goblin squad, the war giant olm squad, and crippled the other ones. The goblins fled as they can and by the end of the assault the map was filled with at least 280 undead due to the evil map and due to necromancers.
i opened up my cage maze and started to wait until the undead would cage trap themselves, but heres when the fun started... you see fresh undead from a siege would normally path into the trap but undead that are struck down and revived or undead generated through other means will not have the same pathing as invader undead. This resulted in at least half of the undead staying outside and not pathing to the trap at once.
the SIEGE tag went away as soon as the last initially sieging undead got caged, but there were still at least 150 undead or so scattered about and looking for brains. It was at this time that a migrant wave arrived... luckily not directly into a undead horde but between the south east horde (the majority of the undead) and the south west horde (a respectable sum of undead, but not as many as the south east). It should be noted that the north side of the map was entirely clean of undead since the goblins arrived at the south east and south west.
my entrance was not useable at this time because i was busy trying to lure the undead into my cage maze, and due to derpwarf pathing, the migrants would inevitably run into one of the hordes and get scared and run about randomly. sent my military of only 14 marksdwarves (4 elites including my mayor and 10 semi-skilled) to attempt to clear the entrance for the dozen migrants while simultaneously closing the cage maze and opening the regular entrance hatch.
Fun resulted when some of my marksdwarves refused to disengage the undead and so i had to pull them back when i could to my firing fortifications around my fortress instead of using them in open field. But by that time i already had a couple marksdwarves with shattered bones through masterwork steel armor. To make things worse a friendly forgotten beast has shown up in my first cavern layer, where a major logging and minor mining operations were taking place. In desperation i disabled the mining labor on most of my miners and made a pick-axe squad to worker-rush the forgotten beast, which did not have any special abilities, but was made of rock.
My miners managed to win against the forgotten beast but one of them was hospitalized. On the surface the necromancers were starting to retreat after a stray bolt managed to get through the undead horde approaching from the west side, and chipped one of their apprentices' bones (note: the undeads i engaged earlier was a much smaller number at the entrance that were going into the cage maze). About a quarter of the undead from the west side started approaching, including several resurrected war giant olms, and where heading for my newly opened entrances that were intended for the migrants.
i kind of gave up on outright saving the migrants at this point, my marksdwarves would die in melee, even the legendary ones as i had no danger room training at all, and undead could hit through steel. My new plan would be to sit behind fortifications and clear any undead that come near my fort, and keeping the necromancers at bay with deadly bolts. Fortunately the undead were mostly very slow, most of the faster ones had run ahead much earlier and got caged in my cage maze. The migrants ran about randomly trying to avoid the undead, 2 of the migrants' pets died and became "missing" adding 2 more dead to the southwest horde; but the undead were too slow and uncoordinated to really catch up with the migrants.
about 2 months has passed since the start of the siege, since the arrival of the goblins. The south east horde has become exhausted from repeatedly trying to assault my fort, and was more or less equal in size to the other horde now, the necromancers had left a while ago. A few of the southwest horde also tried to attack and were too mowed down by bolts. I managed to save the migrants eventually as most undead that pathed to my fort did so and died, and the entranceway was clear. Setting up high traffic routes toward the northern side of my map, the migrants all eventually escaped and where given decent bedrooms right away. Things have calmed down now, with the immediate danger gone, but undead still meander towards my fort; and at least 100 undead remain, scattered about (mostly in the south east and west) and reinforced by zombie kangaroos igneous to the haunted biome.
i stop here, as i've reached a stalemate of sorts with fighting the undead. I cannot engage them directly as i only have 20 marksdwarves, with only 4 elites, 10 regulars, and 6 unarmored fresh recruits. I will wait until they slowly path to my fort and clean up as best as possible, where possible, but that is a tale for another day. Perhaps the dwarven caravan arriving in the late fall will have more luck taking down the lingering undead with their melee caravan escorts.
After the siege (note the little blue icons around the map, those are the undead; also my map is bigger than this, some of the north and west sides are excluded):