Demon Taraka was gaining immense strength and it scared the Gods. He had a blessing from Lord Brahma that only a seven-day old son of Lord Shiva can kill him.
Lord Shiva was meditating in the himalayas, with no intention of producing a son. So all the Gods plotted to get the semen of Lord Shiva through Kamadeva – the God of Love.
And through Kama deva the Gods got Lord Shiva’s semen and Lord Agni carried it to earth and six children were born. The six kritikkas nurtured the babies. When Goddess Parvati saw the babies she instantly fell in love with them and embraced them, and then the babies become one person with six heads and twelve arms known as Skanda or Kartikeya.
Kartikeya, the warrior of the Gods – slayed taraka the demon when he was just 7 days old.
The planet Mars is associated with Skanda or Kartikeya. And Krittika nakshatra is also associated with Lord Kartikeya. People with prominent planets in Kritikka nakshatra may be cared for by more than one mother figure when growing up. They are sharp-tongued and sometimes can say things without careful thinking about the consequences. They are direct in their communication.