adjective
bestial
BES-chul/ˈbestʃəl/
Savage or brutal like a wild animal.
The attacker's bestial cruelty leaves the defenseless person cowering beneath the raised stool.

Etymology
Originally meaning “belonging to a beast,” bestial shifted to describing human behavior as beast-like. Its cruel or savage sense reflects a judgment that such behavior falls below human dignity.
In context
Ancient writers like Ammianus Marcellinus painted the Huns as bestial savages and thought the mass migrations they caused contributed to the eventual fall