Firmly religious
Srimad-Bhagavatam
SB Canto 9
SB 9.2.16, Translation:
From Karūṣa, another son of Manu, came the Kārūṣa dynasty, a family of kṣatriyas. The Kārūṣa kṣatriyas were the kings of the northern direction. They were celebrated protectors of brahminical culture and were all firmly religious.