Kalakeyas

The Kālakeyas () or Kālakhañjas (; Pali: kālakañjā) are a class of Asura in Buddhist and Hindu mythology. They were a powerful, ferocious and cruel clan of the Dānavas.
Kālakā and Pulomā.
The Kālakeyas were the descendants of Kālakā, daughter of Vaiśvānara (son of Danu). Vaiśvānara had three other beautiful daughters: Puloma, Upadānavī, and Hayaśirā
Pulomā was the progenitor of another clan of Dānavas called the "Paulomas". Both Kālakā and Pulomā were married to Kaśyapa, with whom they bore sixty thousand distinguished Dānavas.
The City of Gold.
The Kālakeyas and the Paulomas defended the great city of gold, Hiraṇyapura. Hiraṇyapura was a floating celestial sky-city created by Brahmā as a boon granted to Kālakā and Pulomā to protect their children.
In Hinduism.
The Defeat of the Kālakeyas.
In the time of the Satya Yuga, there was an Asura named Vṛtra. Vṛtra and his associates, the Kālakeyas, were at war with the Devas and causing them to suffer greatly. Indra became deeply dejected. Vishnu aided Indra by lending him his power, to which the other gods responded by lending a portion of their own power. The Ṛṣis followed suit by imparting their energy as well, providing Indra with enough power to vanquish Vṛtra. With the aid of his mighty vajra, Indra managed to slay the Asura king. 
The Kālakeyas fled and hid in the sea, where they plotted against those who upheld righteousness and asceticism. They would remain in the sea during the day and come out at night in order to slaughter and consume sages and Brāhmaṇas in the midst of religious practice. In response to this nuisance, the Devas approached Vishnu and requested him to help them. 
Vishnu explained that the Kālakeyas had hidden themselves in the ocean and could not be easily defeated. He recommended that the Devas seek the help of the sage Agastya in order to dry up the sea.
Agastya drank all of the water in the sea until it became dry, revealing the hidden Kālakeyas. The Devas besieged the Asuras victoriously. Those who survived fled underground into Pātāla. With the Kālakeyas defeated, the Devas asked Agastya to replenish the ocean, to which he replied that he could not, as he had digested the water. Astounded by this feat, the Devas departed to the abode of Brahmā to discuss the restoration of the sea.
In Buddhism.
In Buddhism they are called the Kālakañjakas. Referred to as "terrible-faced," these beings are considered to be a class of Asuras. They were present at the preaching of the Mahāsamaya Sutta and are spoken of as being of a fearsome shape (D.ii.259; also DA.iii.789.820).
They are the very lowest of those beings in the Asura realm.
Bodhisattvas are never born among the Kālakañjakas (J.i.44; BuA.224). Sometimes (E.g., J.v.187; PvA.272), when Asuras are mentioned, the Commentaries explain the word as referring to the Kālakañjakas.
Beings born into this state suffer from excessive thirst, which they are unable to quench even by immersing themselves in the Ganges. (For a story of one of them see VibhA.5). The Kājakañjakas resemble the pretas in shape, sex-life, diet and length of life, and they intermarry with them (Kvu.360).
In popular culture.
Within the Baahubali franchise, "Kalakeya" is the name of the savage barbarian tribes that threatened the kingdom of Mahishmati in the movie . They are again featured in the movie , which introduces the emperor Amarendra Baahubali who describes to the members of the Kuntala kingdom his contribution in vanquishing them.