Heart of the tower
Level 34 Mage Spell
Action
Ritual
Provokes
Yes
Range
Touch
Duration
Permanent
Ritual. 1 watch per 5' section of target tower. Provokes. Tower touched. Permanent. Fortifies an existing tower that can only be destroyed by burning its heart- this magic spell that makes stone impervious to all but 3 attack types, and only one of these in the heart can be used to destroy it easily.