i have no idea why this took forever

There are many "executioners" in the aerie, but only one of them actually carries out the death sentences of prisoners. The executioner is typically heavy set and fairly light on armor. Executioners rely on one-hit kills in the battlefield, and can withstand many hits before succumbing.

The execution of a prisoner is usually held in the middle of the night to prevent anybody who escapes to venture far. If the prisoner happens to know some light magic, the light can be spotted by the officials anyway. It's pretty much a lose-lose situation for an escaped prisoner between treading blind or treading with a giant bullseye.