Ultima III: Exodus

At the beginning of the game, Exodus is terrorizing the land of Sosaria from his stronghold on the Isle of Fire. The player is summoned by Lord British to defeat Exodus, and embarks on a quest that takes him to the lost land of Ambrosia, to the depths of the dungeons of Sosaria to receive powerful magical branding marks and to find the mysterious Time Lord, and finally to the Isle of Fire itself to confront Exodus in his lair.

The game ends immediately upon Exodus’ defeat; but unlike many games in the genre, Exodus cannot simply be killed in battle by a strong party of adventurers, but only through puzzle-solving and by paying attention to the clues given throughout the game. At the end of the game, players were instructed to “REPORT THY VICTORY!” to Origin. Those who did so received a certificate of completion autographed by Richard Garriott.

Source: TheGamesDB