Mayavi

'Mayavi' is Mahi (Mammootty) who has a strange job; he owe up crimes committed by others and go to jail for them, for which he gets a lot of money. He can't stand injustice, but being a criminal himself, he cannot also rub other criminals the wrong way. So he retort to a unique way of roughing up the thugs-- he attack them in the dark or from behind; he finishes his work so fast that nobody would realize who did it, thus earning him the nickname 'Mayavi'. (Keralapals.com) (Summary by iceblox)