Kālī, also known as Kālikā, is the Hindu goddess associated with power, shakti. The name Kali comes from kāla, which means black, time, death, lord of death. Kali means “the black one”. Since Shiva is called Kāla - the eternal time, Kālī, his consort, also means “Time” or “Death” (as in time has come). Hence, Kāli is considered the goddess of time and change. Although sometimes presented as dark and violent, her earliest incarnation as a figure of annihilation still has some influence. Various Shakta Hindu cosmologies, as well as Shākta Tantric beliefs, worship her as the ultimate reality or Brahman. She is also revered as Bhavatārini (literally “redeemer of the universe”). Comparatively recent devotional movements largely conceive Kāli as a benevolent mother goddess.
Kālī is represented as the consort of Lord Shiva, on whose body she is often seen standing. She is the foremost among the DasaMahavidyas, ten fierce Tantric goddesses.
if you ever get a chance to go to Calcutta, you should definitely go during ‘Kali Puja’ which is a festival held in honour of Maa Kali. They erect massive pandals (shrines and clay effigies) and the whole city looks like a colourful mashup of black, red hibiscus and fireworks.