Maa Siddhidatri is the ninth form of Goddess Durga worshiped in Navaratri. The last among the nine forms of Maa Shakti is Goddess Siddhidatri who is worshiped on the ninth or final day of Navratri. Siddhi is a Sanskrit term which means perfection. Goddess Siddhidatri has four arms. She holds a Chakra in her right lower hand and a mace in the upper. In the left lower hand there is a conch and in her upper left hand a lotus flower. She is seated on a lotus flower with the lion as her mount.
The Goddess Siddhidatri is capable of giving all sorts of occult powers and is also the possessor of 26 different wishes to grant her worshipers. All these achievements Siddhi, which according to the Markandaye Purana:- Anima, Mahima, Garima, Laghima, Prapti, Prakaamya, Ish*tva and Vash*tva are 8 siddhis. As per the Brahmavaivart Purana there are 18 types of achievements which are Anima, Mahima, Garima, Ladhima, Prapti, Prakaamya, Ish*tva,Vash*tva, Sarvakaamaal, Saadhita, Sarvagynatva, DurShravana, Parkaayapraveshan, VakaSiddhi, Kalpavrushatva, Shrishti, Samharkaransaamarthya, Amaratva, Sarvanyayakatva, Bhavana and Siddhi.
Legend has it that the Supreme God Shiva got all these siddhis by worshiping Maha Shakti. With her gratitude the half body of Shiva became that of the Goddess Shakti and therefore he also came to be called as Ardhanarishvar. Dev, Danav, Gandharva, Kinnar, Yaksh, Manav, all do worship Maa Siddhidaatri and attain achievements. Maa Durga removes ignorance and she provides the knowledge to realize That or Brahman. That is why She is surrounded by Siddhas, Gandharvas, Yakshas, Demons and Gods who are worshiping her. The Siddhi that she provides is the realization that everything is Supreme Being or Brahman. If a “sadhaka” worships in the prescribed manner with his full faith he acquires all “Siddhis” and nothing remains unattainable from him in the universe.