Kali is one of the ten Mahavidyas of Bhagwati Durga, who incarnated in the world to destroy the wicked, 'Mahakali' is said to be the goddess of creation, protection and destruction.
Kali means - the wife of "Kaal". Kaal is called Lord Shiva and thus 'Jagdamba', the wife of Lord Shiva, turned black, so on the basis of origin, Kaal is unborn and Adi Divine power. It is by the grace of Bhagwati Kali that gods, sages, sages and demons like Brahma, Vishnu, Shiva, etc. are able to attain siddhis. They arise from them and get absorbed in them.
There is a description in the Markandeya Purana, that once two great demons Shumbh and Nishumbha defeated Devraj Indra in a battle and snatched his kingdom and all his rights from them. Thereafter, the two demons, one by one, defeated all the deities and removed them. The expelled gods started invoking Aparjita Devi to protect their life and honor, because before this, on the call of the gods, the goddess had killed Mahishasura and gave him a boon that whenever you remember me in the time of calamity, I will give you all your troubled moments. I'll put it away.
Remembering this, all the gods reached the Himalayas and started praising Vishnu Maya Bhagwati. When all the gods were praising Bhagwati for the destruction of calamity, at the same time Shri Parvati came for bath in the Ganges and asked the deities, "Whose are you praying and why?"
At that time, appearing from the body of Parvati, Shiva is praying.
Shiva (Ambika) appeared from the corpus of the goddess, hence she is also known by the name "Kaushiki". With the appearance of Kaushiki, Parvati ji turned into a black form and became famous by the name "Kalika".
Ambika Devi walking in the Himalayas in the most beautiful form was seen by the Char Chand-Mund of Shumbh-Nishumbha and went to Shumbh, praising her form, and prayed to make her his Panigrahita.
Hearing the words of Chand-Munda, Shumbha sent Mahaasura as his messenger to the goddess and invited him to come to her. Mahaasura praised the demon king as ordered by Shumbh and advised to get married. Hearing the messenger, the goddess said, "Whatever you said, Shumbha and Nishumbha will be equally powerful, but I cannot accept their proposal, because I have taken a vow that one who defeats me in battle will break my pride, He can be my recruit."
Hearing such words of the Goddess, the great demon, full of anger, came to the demon king and narrated the whole story. Hearing the words of the messenger, the demon king became very angry and sent Chand-Mund with a huge army and said, "Kill the goddess and her lion, tie Ambika and bring it to me."
As soon as the order was received, the demons like Chand-Munda etc. started trying to capture the goddess with the Chaturangini army armed with various weapons. Ambika got very angry. Due to anger, his face turned black, the eyebrows on the forehead of the goddess became crooked, and then the black goddess with a terrible face appeared with a sword and a loop. She broke down on the demon army with great speed, and killed them and started eating them. Thus Kali crushed the army of evil demons. With a roaring roar, Kupita Kali killed Chand and Munda too. Kali was also known as 'Chamunda' for killing Chand-Munda.
On hearing about the death of Chand-Munda, the demon king Shumbha became very angry and proceeded with Udayuddha, Kambu, Kalik, Maurya, Daurhrid, Kalkeya etc. Lethal strikes began.
Very angry, Kali spread her mouth and roared loudly. At the same time, for the destruction of the demons and for the development of the gods, the powers of Brahma, Vishnu, Shiva, Kartik etc., having been endowed with great valor and divine weapons, came to Chandika, and then the Kali Daitya army, coordinated in the most divine powers, came to destroy the army. It took Seeing such a great destruction, the Asuras started running away, seeing them running away, Commander Raktabeej got very angry and came to fight. As soon as a drop of blood from the body of Raktabeej fell on the earth, another demon as strong as him was born. The Goddess's senses thrashed her with a thunderbolt, a lot of blood started flowing from her body as soon as the thunderbolt struck her and many mighty warriors like Raktbeej appeared. The whole world was engulfed by those demons born of the demon's blood and the gods became very frightened, seeing the deities in fear, the goddess said to Kali "O Chamunde! You spread your mouth wide and the blood falling from my weapon, the dots and dots." Devour the great monsters that have arisen from you with your swift mouth. You keep roaming on the battlefield eating these great blood-borne monsters, then only these demons will perish, because new monsters will not be born if you are eaten by them."
The goddess then struck Raktabeej with a trident and Kali readily swallowed the blood of Raktabeej in her mouth. In this way the goddess killed the bloodless Mahasura Raktabeej with the weapons of prong, thunderbolt, arrow, sword etc.