I read this short story about 15 years ago, in English.
It tells the story of an off-world human colony attacked by a pair of tentacled aliens. These aliens intend to eat all the humans in the colony, but when the shepherd is brought before them he attempts to communicate with them, finally convincing them to leave the humans as cattle, eating human flesh without killing all the humans.
The aliens give him a shepherd's crook that can pacify the humans and an axe (or similar cutting instrument) to harvest the flesh without killing the humans. This goes on for several years.
Finally a human spaceship arrives and kills the aliens. The rescuers see the shepherd's actions as unique, since typically these aliens simply kill and devour all humans in a short time, and here the colony was kept alive (although with missing limbs, etc.) for years. The visiting humans tell the colonists they should be grateful for the shepherd. After the visiting humans leave, the colonists
use the axe to strip the shepherd of all limbs and organs he doesn't need in order to be kept alive, so that he suffers, instead of thanking him.
Sadly searching this description doesn't come up with anything.