D&D 5E Dispelling Permanent spells

[NotAYakk]

By the rules as written, dispelling a teleportation circle, hallow or other permanent spell effect is ridiculously easy. Any character able to cast 3rd level spells can do it with at worst a few days of work. And Hallow is a 5th level spell that requires 1000 gp of money and 24 hours to cast... which a level-appropriate foe can drop reliably in a single action.

So here is an attempt at mechanics to make it possible, but not automatic:

Dispel Magic:
When dispel magic is used on a permanent spell effect you must always make a spellcasting ability check with a DC of 20 plus the spell level. You gain a bonus to your check equal to the slot level used to cast dispel magic. If you fail on this check, you cannot try to dispel the same effect again for another week.

So now a level 11 character with 20 wisdom using a 5th level slot can attempt to dispel Hallow. The DC is 25 and the player has a +10 bonus to the check; so a 30% success chance. It will on average take 3 weeks to take the Hallow down.

A level 11 abjurer has a +14 bonus, for a 50% chance of success. A level 11 20 cha bard has a +12 bonus, for a 40% chance.

A level 20 abjurer using a 9th level slot has a +20 bonus to the check, and a 80% chance of success.

What do you think? Should I make it harder? The "1 week break" makes it hard for a single caster to spam-dispel, but armies of lesser spellcasters can take down pretty high level effects.

I could scale the slot level bonuses to 2* spell level on both DC and on check. That would make Hallow be a DC 30, and a level 5 wizard with 16 int would have 0 chance to dispel it.

 

[jasper]

"Well Well well, " message Kirk to Not a yak, " You have upset my buddy Scotty. Mr. Spock, Phaser that location! and Wax that goatee."
Yes it is easy. But will you survive the logical reactions of you encounter.

 

[Lanefan]

Idea's good, though I think I'd throw in that a natural 20 gets it no matter what so as to still give the lower-level types some faint hope.

And-or another option might be to put a 'kick-back' into permanent spells such that unsuccessful attempts to dispel them cause problems of some sort for the caster for a while (e.g. cannot cast dispel magic again at all for three days; or caster takes [permanent spell's level +5] damage that cannot be recovered by any means for 48 hours, or similar)

 

[Li Shenron]

I like the idea, but I would not make it a general house rule... I'd rather simply make ad-hoc rulings if the story requires, so for example if you want a temple to feature a permanently hallowed area, just rule that it's not the usual spell but something else.

 

[MonkeezOnFire]

I would rule that once a spell becomes permanent it can no longer be dispelled by Dispel Magic. My thinking here is that once the effects are permanent the spell it becomes more like the magic of a magic weapon. It's an effect created by magic, but magic is no longer needed to sustain it. Of course, like magic items these effects would still be able to be destroyed, it's just much more difficult than casting a level 3 spell.

I know this isn't RAW, since you could point to Wall of Stone which says "If you maintain your concentration on this spell for its whole duration, the wall becomes permanent and can't be dispelled." Since the other spells lack the can't be dispelled distinction it can be argued that they can. But the above is a ruling that I would make for my game.

 

[NotAYakk]

I sort of want this kind of thing to be predictable for PCs, both on the casting and dispelling end.

As it stands, most of those "permanent" spells are pretty useless in a world where dispel magic capable enemies are around. Use Hallow to defend a church? If the enemy has almost any spellcasters of 5th level or higher this is a pointless thing to do. True Polymorph and concentrate for an hour to turn a mermaid into a human so she can marry a prince? Any journeyman mage can disrupt that enchantment.

Permanent spells include True Polymorph, Hallow, Symbol, Teleportation Circle, Glyph of Warding, Guards and Wards, Simulacrum. Probably more than I forgot, but the pattern is pretty clear.

Of them, True Polymorph and Simulacrum could have real balance impacts from this. Both are seemingly strong spells that are actually a joke once you realize how easy they are to drop.

Of the list of permanent spells, they all require large amounts of time investment and often gold to cast the spell, which is as fragile as a crystal goblet against even a much weaker mage.