Planescape: Torment

"A CRPG set in the Dungeons & Dragons setting of Planescape in which The Nameless One, an immortal amnesiac, sets off on a quest across the infinite Planes and gathers a party of conflicted companions to find out who he is and reclaim his mortality. Throughout it, he faces the consequences of the horrors he committed in his past lives and tries to find the root of all the torment plaguing his companions and the Planes."