After getting the generic "Urist is missing" message I paused the game. Found the corpse on the bedroom level. 10 minutes of detective work later I found him.
" ... The High Council has found you guilty! Since no physical punishment could ever make up for the suffering you have brought upon the mountain homes, you will not be sentenced for hammering. And your death will not bring back the lives you have taken during your unnaturally long life. No! Death would only free you from the course that has fallen upon you!
Instead, we will give you an eternity to make up for all the wrong doings you brought upon your brothers and sisters!
For you will be locked in a 2 x 2 cell with only a chair and a table. No bed, no food, NO BOOZE!
And you will stay locked inside that cell until you have counted everything! Every block of rock, every bag of sand, every metal bar and every piece of thread in the fort!
Once everything is precisely written down, you will be set free."
The Vampire: HA! You worthless mortals! I will play your stupid GAME! For I accept your challenge! A couple of years from now I will walk out of this hole as a free dorf!
And so he walked in to his prison. There he stayed for years. He worked hard, updating the records, slowly getting better. But whenever he thought that the end is near, something happened.
Then he discovered, that for as long as the fort lives, the stockpiles need to be updated.
Like Sisyphus, the vampire was trapped in a never ending loop. For whenever he started the updated, it was already out of date, for all of eternity, till the FPS lag, slowly, freezes him in place...