The makers wanted a girl who could sing well, and cast Shobana as Kaveri after discovering her at a school event. Sivasankar, who became known as "Mahanadhi" Shankar, was cast as the prison warden Thulukaanam as the makers wanted someone who could perform stunts as well as act. He was already a stuntman, and was recommended to Bharathi by Dharma.
The creators sought a singer, and chose Shobana to play Kaveri after spotting her at an event. Sivasankar, known as "Mahanadhi" Shankar, was cast as the prison warden Thulukaanam because they needed someone who could perform stunts alongside acting. He already had stunt experience and was recommended by Dharma to Bharathi.