The soul of Darkness) is a 1967 Indian Malayalam-language film directed by P. Bhaskaran and written by M. T. Vasudevan Nair based on his own short story of the same name.

The film is about a mentally unstable youth born into a matriarchal family who is forced to live as a mad man in chains and who is misunderstood and ill-treated by everyone except his uncle's daughter.

[2] The film features music by M. S. Baburaj, cinematography by E. N. Balakrishnan and editing by G. Venkitaraman and Das.

[3][4][5] Nazir himself rated his role of Velayudhan in Iruttinte Athmavu and as the swashbuckling folk hero Thampan in Padayottam as his best.

[10] The film was part of MT's trilogy of political melodramas – the other two being Murappennu (1965) and Asuravithu (1968), both directed by A.