Mahākāla is a deity common to Hinduism and Buddhism.
Mahākāla and companions
Indian Buddhist Mahakala, 11th–12th century, Bihar
A basalt statue of Mahākāla from Odisha, dated to the Pala period (eastern Bengal, 1100–1200 CE). Victoria and Albert Museum, London
Black-Cloaked Mahākāla
A dharmapāla is a type of wrathful god in Buddhism. The name means "dharma protector" in Sanskrit, and the dharmapālas are also known as the Defenders of the Justice (Dharma), or the Guardians of the Law. There are two kinds of dharmapala, Worldly Guardians (lokapala) and Wisdom Protectors (jnanapala). Only Wisdom Protectors are enlightened beings.
Tibetan (Citipati mask depicting Mahākāla)