We know that Shri Rama took birth to rid the three worlds of the tyranny of Ravana. But I recently came across a verse in the Valmiki Ramayan that says that Seeta was also born for the same purpose!
Valmiki Ramayan Yuddha Kanda Sarga 94 mentions:
All the celestials together with Indra and others, got propitiated by Shiva the lord of destruction, with the ensign of a bull on his flag-staff and who destroyed the three strong cities built of gold, silver and iron in the sky, air and earth for demons. The gracious Shiva spoke the following words to the celestials: 'For your benefit, a woman will be born, for causing destruction of the demons.'
This Seetha, the destroyer of demons, employed by the celestials, will consume us along with Ravana, as in the past hunger consumed the demons."
My question is - Is the story detailed anywhere else in the Ramayana or is this claim corroborated in any other scripture?