Sunil Kumar, known by his stage name Narain, is an Indian actor, who has starred in Malayalam, Tamil and Telugu films. He made his debut in Adoor Gopalakrishnan's Nizhalkuthu (2002), followed by performances in Malayalam films 4 the People (2004), Achuvinte Amma (2005), and Classmates (2006). Narain's Tamil and Telugu debuts were in Mysskin's Chithiram Pesuthadi (2006) and Jayaraj's Yuvasena (2004).

Nizhalkuthu is a 2002 Indian film in Malayalam directed, written and co-produced by Adoor Gopalakrishnan. The film explores the recesses of the human consciousness. It stars Oduvil Unnikrishnan in the lead with actors Narain, Murali, Sukumari, Reeja, Nedumudi Venu, Vijayaraghavan, Jagathi Sreekumar and Tara Kalyan in supporting roles. It premiered at the Venice Film Festival in the Orizzonti section and received critical acclaim. The film was awarded the FIPRESCI Prize at the festival.