The Hindu god associated with the Prahlada legend of Holi is Vishnu.
In the story, Prahlada is the devout son of the asura king Hiranyakashipu, who demands that everyone worship him instead of Vishnu. Prahlada refuses, remaining devoted to Vishnu despite repeated attempts on his life.
Hiranyakashipu’s sister Holika then tries to burn Prahlada in a fire, but Prahlada survives while Holika is destroyed. Vishnu later appears as Narasimha, his half-man, half-lion avatar, and defeats Hiranyakashipu. The story is commemorated by Holika Dahan, the bonfire held before the colorful celebrations.
A common mix-up is to answer Narasimha or Krishna. Narasimha is the form Vishnu takes in the story, while Krishna is central to other Holi traditions, especially those connected with Radha and the Braj region.