The last night of Navaratri is known as Maha Navami. The NavDugra whom we worship is Siddhidatri. She has the ability to grant worshippers their wishes.
The eighth night of Navratri is known as Durgashtami. It commemorates the day on which Goddess Durga gained victory over the demon Maheshasura.
Kalaratri is the NavDurga whom we worship on the 7th night of Navratri. She is the most fierce of the 9 goddess and teaches us to follow our true path.
On the 6th night of Navratri, we worship the NavDurga in the form of Katyayani Devi. For those who are single and desire a partner, it is especially propitious to worship this goddess.
The fifth night of Navratri is known as Lalita Panchami. We worship the NavDurga in the form of Skandamata. She is the mother of Skanda or Kartikeya.
The fourth night of Navaratri is known as Chaturthi. We worship the NavDurga in the form of Kushmanda Devi. She is said to have created the universe from her smile.