The KROZ series of games was written by Scott Miller, one of the founders of Apogee Software (the software company that released Wolfenstein 3D for id Software).
The games include:
1. Caverns of Kroz
2. Dungeons of Kroz
3. Kingdom of Kroz
4. Return to Kroz
5. Temple of Kroz
6. The Final Crusade of Kroz
7. The Lost Adventures of Kroz
Of these games, the most popular is Kingdom of Kroz, because it was the only one of the seven released as shareware, which happened in 1987. This is what hooked many of the people on the games, and earned Scott Miller enough to invest in his first mutual fund.
An interesting note - KROZ spelled backwards is ZORK, a game put out by Infocom - which happened to be one of Scott Miller's favorite games.
All seven of the games were adventure/puzzle games, where the object was to navigate a maze filled with various traps, monsters, whips, gems, and other goodies. They were all written using ascii. For those of you who aren't familiar with the ascii character set, this means that the graphics were composed of letters and symbols from the keyboard in addition to a few limited graphics characters. All in 16 bright colors. Did I mention these games were old school?