While the deities hailed the glory of Kartikeya for having killed Tarakasur, Kartikeya himself was saddened by his act. He told the deities–‘I regret for having killed Tarakasur because he was a great devotee of Lord Shiva. Is there any way to atone for my sin?’
Lord Vishnu consoled him—‘Killing a wicked person, who nourishes himself on the blood of innocent people, is not a sinful deed. But, still, if you feel guilty then there is no better way to atone for your sin than worshipping Lord Shiva. Install Shivalingas and worship them with deep devotion.’ Kartikeya instructed Vishnukarma to make three divine Shivalingas. Later on Kartikeya installed these Shivalingas at three different places and worshipped them with appropriate rituals. In course of time these three holy places came to be known as Pratigyeshwar, Kapaleshwar and Kumareshwar. Kartikeya, while worshipping at Kapaleshwar sprinkled holy water on the Shivalinga and prayed so that Tarakasur’s soul rested in peace. He also offered sesame seeds to Lord Kapaleshwar and prayed –‘May my offerings made in the form of sesame seeds reach Tarak–the descendant of Sage Kashyap.’
This way, Kartikeya was absolved of his sins.