In Hindu mythology, what demon was slain by the man-lion avatar of Vishnu?

In Hindu mythology, Hiranyakashipu was slain by Narasimha, the man-lion avatar of Vishnu.

Hiranyakashipu is a powerful daitya king and one of the major asura antagonists in the Puranic tradition. After his brother Hiranyaksha was killed by Vishnu’s boar avatar, Varaha, Hiranyakashipu performed severe austerities to obtain protection from death. He then persecuted Vishnu’s devotees and demanded that people worship him instead.

His son Prahlada remained devoted to Vishnu. When Hiranyakashipu challenged Prahlada’s claim that Vishnu was everywhere, he struck a pillar and Narasimha emerged from it. Narasimha was neither fully human nor fully animal, allowing Vishnu to circumvent the conditions of Hiranyakashipu’s boon.

The killing takes place at twilight, neither day nor night, on a threshold, neither indoors nor outdoors. Narasimha places the asura on his lap, neither earth nor sky, and tears him apart with claws rather than a conventional weapon. Hiranyakashipu is therefore not to be confused with Hiranyaksha, who was killed by Varaha, or Ravana, who belongs to the Ramayana.