1991, Westwood Studios / Strategic Simulations, Inc.
The Legend of Darkmoon used a modified version of the first games engine, added outdoor areas and greatly increased the amount of interaction the player had with their environment, along with a substantial amount more 'roleplaying' aspects to the game. You go to an inn to rest but a note gets slipped to you from Khelben Blackstaff (Archmage of Waterdeep) who says that he sent a scout (Amber, a female elven thief/mage of neutral good alignment) to destroy the evil temple known as Darkmoon but she has not returned...