brutalizar

To brutalize — to treat someone with extreme violence or cruelty, or reflexively (brutalizarse) to become coarsened/brutal through exposure to violence. A formal, fairly uncommon verb mostly seen in journalism, human rights reporting, or literary writing.

• El informe denuncia cómo se brutalizó a los prisioneros. — The report denounces how the prisoners were brutalized.
• La guerra terminó brutalizando a toda una generación. — The war ended up brutalizing an entire generation.
• Se brutalizó tras años de violencia constante. — He became brutalized after years of constant violence.

This is a strong, formal word for extreme cruelty — using it for everyday rough treatment overstates the case; maltratar covers ordinary mistreatment without the same intensity.