It is possible to sever the face off of anything that has one, creating a gruesome mask that can be worn over your own face. This grisly trophy provides a boost to your ego from +1 to +3 depending on the level of the creature it came from when equipped and changes your relationship with the creature's faction or factions by -500. Your own severed face or that of a companion does not cause any reputation drop.
Some creatures have a different name for their "face", but which still functions this way when severed (and is described as their face in the item details).
Creatures whose faction affiliation is overridden by modifications from their base template will provide faces that affect those factions instead of their normal ones; for example, the face of a "dromad trader and psychic thrall" will give -500 reputation with the Seekers of the Sightless Way, not dromad traders. Scaling encounter strength can also increase the ego modifier (it appears to be based on creature level).
Be careful when interacting with face items in your Equipment screen, since unlike most other equipment, the default action for them isn't "remove", but "eat".
|Face source||Ego modifier||Factions affected|
|Agolzvuv||+2||insects, the Girsh|
|Beetlebum||+1||grazing hedonists, insects|
|Dromad Trader||+2||dromad traders|
|Echelstadt II, High Priest of the Stilt||+2||Mechanimists|
|Elder Irudad||+3||Villagers of Joppa|
|Eyeless King Crab||+1||crabs|
|Gelatinous Ovoid ("sensory bulb", not face)||+2||oozes|
|Goatfolk Thrall||+1||the Children of Mamon|
|Great Magma Crab||+3||crabs|
|Great Saltback||+2||dromad traders, tortoises|
|Knight Templar||+2||the Putus Templar|
|Mehmet||+2||Villagers of Joppa|
|Oboroqoru, Ape God||+3||apes, grazing hedonists|
|Rocket Turret ("sensor array", not face)||+1||robots|
|Rodanis Y||+3||robots, Barathrumites|
|Saad Amus The Sky-Bear||+3||beasts|
|Salt Kraken||+3||Grazing Hedonists, Mollusks|
|Warden Ualraig||+3||Fellowship of Wardens|
|Warmonger amongst the True (Putus Templar hero)||+3||the Putus Templar|
|Watervine Farmer||+1||Villagers of Joppa|
|Wild-Eyed Watervine Merchant||+1||grazing hedonists, Children of Mamon|
|Worm of the Earth||+1||worms|