He was harsh to kings and soldiers who refused to surrender, but neither him nor his brother ever annexed territories or oppressed the common people. They only collected tributes from the vanquished kings. They even treated enemy prisoners kindly, and gave them land-grants to settle.
Despite being harsh towards those who resisted, the king and his brother never took over territory or mistreated ordinary citizens. Instead, they only demanded tribute from conquered kings.  They were also known for treating captured enemies fairly, offering them land to settle in as a sign of mercy.