I finally got to the point where I can make a successful, unbreakable fortress of peace and love (invincible adamantine-clad military, jewel-encrusted masterwork adamantine statues in the dining hall, rooms for every dwarf, etc.). I then downloaded .31.16 and started doing challenge forts. My first one ("Angercrypts") was on an area that was half jungle and half sinister mountain. After fighting off waves of skeleton goats and hoary marmots, my dwarves carved out a modest hall in the mountain. An abundance of coal & magnetite and a lucky migrant wave consisting of several skilled metalworkers (high master weaponsmith who immediately went fey and produced an artifact iron shortsword, Adept armorer, high master blacksmith and metalcrafter) led to the development of an iron industry. A little while later a hunter dragged in an elephant corpse, which produced enough meat to feed the entire fortress for six months. I quickly set out to capture and tame as many elephants as possible. All was looking good, aside from the occasional skeleton goat herd running through my traps and scaring the fortress.
Then, triple goblin ambush on the first human caravan. The human guards held them off long enough for my meager and untested militia force to assemble (one swordsdwarf with the artifact sword, an axedwarf, and two marksdwarves). The two melee dwarves rushed into the fray while the marksdwarves took shots at anything they saw. The the axedwarf, after scoring one kill and one mortal wounding, was cut off from the valiant swordsdwarf and was cut to pieces. Shortly therafter, the goblins retreated. I noticed that one of my elephants had gored a goblin to death, and I looked it up and found out that elephants were trainable. A crack team of war elephants soon became my fortress's primary line of defense. Seriously, war elephants kick ass. Their tusks eviscerate unarmored enemies, their huge feet crush everything else into paste, and it takes an incredible amount of punishment to stop them. After a quick funeral and a quick draft, I felt safe.
Yeah, it wasn't to last. I breached the first cavern layer on my search for the marble layer allegedly somewhere underneath me. On every other fort I had, this wasn't a problem because the creatures were fairly benign. Well, this was an evil biome. The only thing scarier than an infestation of cave crocodiles is an infestation of undead cave crocodiles. After losing two explorers to them, I sent my military to eradicate the creepy crocs. Unfortunately, while they were away, a skeleton blind cave ogre (HOW DO YOU TELL THAT IT IS BLIND!?) snuck up the mining shaft and killed three more dwarves. My retired elephant-hunter managed to take it out before I had to recall the militia, and some shiny new silver statues in the meeting hall took care of the potential tantrum spiral. Unfortunately, I had lost my best armorer. I had to train a new one up from scratch, meaning that the new recruits I was about to draft would have low quality armor. Then, a forgotten beast with deadly blood and another triple goblin ambush (at least they ambushed the elven caravan this time) appeared at the same time. I sent my 2 marksdwarves to take care of the FB and my new recruits and veteran to take care of the ambush. I also tried releasing the elephants, but I did it too early and they just ran over to the meeting hall. The recruits did poorly, getting torn apart by goblin bowmen almost immediately. Only one macedwarf, the one that inherited the axedwarf's high quality armor, and the artifact-wielder survived. They successfully dodged or blocked the rest of the bowgoblin's shots and then charged the speargoblins that were with them.
Meanwhile, the battle with the FB wasn't going too well either. My plan to take it out with ranged weapons worked well until the captain ran out of ammo and charged it. He bashed it on the head ineffectively with his crossbow and got his arm shattered for his mistake. The other marksdwarf kept firing while the FB tore his comrade to pieces, until he too ran out of ammo and the brave marksdwarf captain died. Backed into a wall, he could only watch in horror as the bolt-filled, bleeding three-eyed giant crocodile lumbered towards him. Raising his crossbow, the marksdwarf prepared to charge in and try to bash it to death when the FB suddenly collapsed dead in a pool of its own toxic blood. Incredibly, my marksdwarf hadn't contacted any of that blood. He was quickly given more ammo and sent up to assist the rest of the military while my masons sealed off the contaminated area.
On the surface, the battle was a disaster. The swordsdwarf was taken down with a lucky hit to the foot and quickly butchered (but not before earning a title- he was a brave dwarf). The macedwarf, who had been lucky enough to avoid being surrounded, charged off after the fleeing bowgoblins, leaving the marksdwarf to fight alone. He took out two already heavily-injured goblins before getting killed. The remaining goblins rushed triumphantly into my fortress. All was lost.
Just kidding. What they found wasn't a bunch of terrified, helpless civilians. What they found was five times their worst nightmare: four thousand kilograms of thick hide, jagged tusks, and crushing feet, trained for war and thirsting for blood. It was glorious: the goblins' spears did little more than enrage the elephants while they gored and flattened the green menace. The survivor ran away, only to be met by the surviving macedwarf who was eager to avenge his fallen comrades. One title-earning and large funeral later, a new batch of recruits is learning from their scarred commander while the mechanics work on a more effective elephant release method. I guess it's time to go find that marble so the recruits have a better survival rate than one per ambush.