Castle, The Palace, Haunted Valley, Gloomy Mountains, Complex Of Towers, Angkor
Executioners are elite monsters encountered in Chapter 4 of Painkiller. They wield axes with spikes on them and wear red robes with their stomachs exposed. The first kind, with red robes, will simply walk over to you to slash you with his axes. Blow his stomach open (And note the red lava inside) to kill him. However, if they see a dead body lying around, they'll rush over to it and slice it, releasing Spiders. However, these enemies are big pushovers as they have no ranged attack. You'll encounter them in Castle and in The Palace. This version also appears in Painkiller: Overdose in Haunted Valley, in Painkiller Redemption in The Complex Of Towers and in Painkiller Recurring Evil in Angkor as well.
These bruisers are encountered in Babel. Besides having more health, they can use their axes like Painkillers - launching the spike and sticking it to the wall, leaving a laser trail that damages. If the spikes hit you though, you will be launched towards the Executioner. However, they behave just like them even with this ability, so treat them the same - Blow their stomachs open.