From the introduction: The Tomb of Orr is not like other levels of Dragon’s Delve. The entire level is hidden, and most of the residents of the dungeon don’t even know it’s there. Orr died of an interplanar wasting disease for which no cure was ever found--even the most potent spells had no effect. The wizard-priest himself supervised much of the construction of his own tomb. When he became too ill to do so, he acquired the services of a satyr named Jumanik to finish the job for him. Jumanik put many of the puzzles in the level where Orr would have just put straightforward wards. The satyr also left clues out in the dungeon (such as in area 308) suggesting where the tomb could be found--he thought that if no one encountered his traps and puzzles, there would be no point to them.