Imprisonment

When an imprisonment spell is cast and the victim is touched, the recipient is entombed in a state of suspended animation (cf. temporal stasis) in a small sphere far below the surface of the earth. 

The victim remains there unless a reverse of the spell, with the creature's name and background, is cast. 

Magical search by crystal ball, a locate objects spell or similar means will not reveal the fact that a creature is imprisoned. 

The reverse (freedom) spell will cause the appearance of the victim at the spot he, she or it was entombed and sunk into the earth.

There is a 10% chance that 1 to 100 other creatures will be freed from imprisonment at the same time if the magic-user does not perfectly get the name and background of the creature to be freed. The spell only works if the name and background of the victim are known.

To find what number of creatures are freed, roll percentile dice to find the density of imprisoned creatures before rolling for the number. Multiply the first roll by the second, rounding any remainders to the nearest whole. 

For each such creature freed there is only a 10% chance that it will be in the area of the spell caster. Use the RANDOM MONSTER TABLES of APPENDIX C for these, using d20 for level, any number of 9 or higher indicating a 9th level monster.