In the winter of 257, my fortresses, Powerfinger,
was going incredibly well. All my 140 dwarfs had high-quality bedrooms, my tavern was legendary(and for citizens only at present), and i was churning out steel weapons and armor for my growing military. My dwarfs were busy building a vast system of pumps to transport water 80z from the 2nd cavern(i had half-built it by the time i discovered the first cavern), to my main fortress, as well as the vast number of windmills needed to power it. The only deaths had been a two year old(killed by a hill titan), and a spear-dwarf(dodged into an underground lake while killing crundles). But then disaster struck.
I ordered everyone inside and sent my older, more experienced military squad against her. They were only moderately skilled, but they were well equipped and they had managed to kill a hill titan and a forgotten beast(made of coral), with no losses(except the two year old). As such i expected a victory, if a difficult one. But the dragon cared not for my expectations and killed all nine soldiers i sent against her, with only minor injuries to herself. She then proceeded to set the forest on fire, a disaster as i have no coal and my magma sea is 160z levels down(though not as much as i expected, as most of the trees survived with only minor charring)
My trade deport(and 1/5th of my fortresses wealth) went up in smoke, but a far greater catastrophe was the loss of my wind-farm. This wind-farm, which powered not only the future water pumps but also several mine-cart railways, contained more windmills than i have dwarfs. Fortunately, the power-supply system underneath suffered only minor damage, so rebuilding it should be quicker than starting from scratch.
Having destroyed the surface, the dragon proceeded to kick down Powerfingers front door(which took surprisingly long), but by the time she got broke through i had built cage traps in the entrance hallway, which locked her up to be disposed of on my terms.