I have a question, or concern how have you, that is about turning invaders to ghouls and prisoners.
I was playing in the Scorching Shiv in a flat region with shallow metals, deep metals, and flux. No river and ridiculously flat. I have been surviving off strawberry wine and fisherberry wine and the meat gained from killing snakes and scorpions. Not a glorious start for any Aspiring necromancer world leader. But that's not the problem. It was year 79, 3 years after embark, when my first invasion occurred. The invasion was 3 squads of 20 units of Expert Macedwarves, half belonging to the jeweler's guild for some reason or another.
I captured about 25 of them, striped them of all weapons and armor, then 10 to my corruption chamber room and the rest to the Prison cells to imprison them. BTW when these dwarves were caged, the siege ended and the rest of the dwarves just left, making me scratch my head in confusion but didn't really question it because i was still alive.
I used the reaction in the Corruption Chamber to turn caged prisoners into ghouls. The reaction went through, first turning them all around the chamber into screaming prisoners as intended. After unpausing each dwarf turned from a screaming prisoner into a Ghoul, even showed under the units window. When released from their cages since they said that they transformed to a ghoul and showed in my civilians tab, they started murdering everything. Eventually they all died to my Skele Hammer-men, leaving 2 warlocks and 5 Bloodsteel skeles. I then went to turn the remaining invaders to prisoners using the Prison Cell. After the message saying that "target dwarf" has transformed into a prisoner, i opened the cages and pastured them into the cell room.
Again, the prisoners killed my remaining Warlocks. And with only skeles, the warlock civ can't really do anything. So was there something i was doing wrong here or was is just dumb luck and didn't fully turn?