A more potent form of the lesser sign of sealing, this spell allows the caster to guard an item or portal and prevent all other creatures from opening or passing through the sealed item or surface. The greater sign has several effects; first of all, it affects a doorway or item that opens (a chest, for instance) as a wizard lock spell. If placed in an open corridor or archway to prevent passage, the greater sign creates a magical barrier that repels all who try to pass.
Second, the greater sign greatly strengthens the physical structure of any door or item it is placed upon, granting a +6 bonus on any item saving throws and allowing the item or door to ignore 1 point of damage per caster level from any attack. For example, a greater sign cast by a 12th-level wizard would reduce the damage of any blow or spell by 12 points, so a fighter armed with a broad sword (maximum damage of 8 points) could never hack through a door protected by the sign.
Finally, if the protected doorway or item is forced open or destroyed by any means, the sign itself is not only destroyed, but also releases a spell upon the offending creature. The spell held by the sign is cast into the ward when the greater sign is created, and any spell the caster has memorized may be used in this way, from a fireball or shocking grasp to a very nasty wish or polymorph. The range of the sign’s retributive spell is 10 yards per caster level, so it is possible to destroy the warding from a safe distance.
The sign is displayed in plain sight, and most wizards will recognize it for what it is. The caster cannot specify particular creatures or conditions for the sign’s operation; it functions against any creature that attempts to pass it, although the wizard can freely pass through his own sign without activating it. The greater sign can be removed by the caster, thus ending the spell, or it can be defeated by a limited wish or wish spell cast by a wizard of equal or higher level than the original caster; it cannot be dispelled.
The material component for a greater sign is a powdered diamond worth at least 1,000 gold pieces.