From the introduction: Level 4 of Dragon’s Delve was created by the infamous Red Saint to house prisoners after his host defeated Lord Saral and his forces.You can read more about that in the History document, or in The Song of Azassarah. The prison is guarded by various constructs and magical wards, although in the intervening years, intruders have intruded, and now the level has other inhabitants as well, various time-lost wanderers and squatters. These newcomers have also altered things in ways that the Red Priest could not have predicted.