Dhumravarna defeated the demon Ahamkarasur, the demon of self-infatuation. Once Lord Brahma bestowed on the Sun deity the lordship over the 'world of activities'. One day, a thought dawned in the mind of Sun: "All the worlds are governed by Karma—-activities; and by virtue of my being the Lord of Karma Rajya, I can consider myself to be the supreme governor of all the worlds. As this thought passed his mind, he happened to sneeze and out of the sneeze there arose a demon.
He went down to the world of Asuras and Sukracharya gave him the name “Aham" on account of his birth from the ego of Sun. He meditated on Lord Ganesha, who appeared before him in the form of Dhumravarna and blessed him to be the sovereign ruler of all the three worlds. Tired of the demonic rule of Aham, the Devas meditated upon Lord Ganesha for salvation, and the Lord descended to their rescue, Lord Ganesha in the form of Dhumravarna subdued the demon Aham.