D&D Spellcasting: Pushing Beyond Your Limits

It's been a while since I last posted, so I figured I'd put up a little something I've been thinking about when it comes to gaming.

What if magic-users in the D20 system could somehow push beyond their limitations? What would be the risks involved?

Well, the D20 Wheel of Time book from the early days of 3rd edition has a system for Aes Sedai channelers of the One Power to do just that. So... why not adapt some of those rules for sorcerers and wizards in 3.5 D&D or Pathfinder? I've house-ruled the ability for wizards to overprepare and sorcerers to overcast their spells and fiddled with the rules for doing so until they fit how I wanted to use them.

First, there are two things a caster can do. They can attempt to cast or prepare more spells than available slots, or they can attempt to cast spells that are, as of yet, beyond their ability to know, or have been enhanced with metamagic feats beyond the magic-user's capacity to cast or prepare.

Once the caster has decided to do one of those things, he or she must make a Concentration Check. Finding the Difficulty Class isn't hard.

To cast/prepare a spell with no slots left: DC = 15 + (spell level x 5)

To cast/prepare a spell higher than highest possible slot: DC = 15 + (5[spell level - highest possible slot level]).

It looks more complicated than it is. Check out the chart below.

Concentration Check DC	Overpreparing/Overcasting Attempt	Fortitude Save DC
15	Cast/prepare a 0-level spell with no slots left	15
20	Cast/prepare a 1st level spell with no slots left	25
25	Cast/prepare a 2nd level spell with no slots left	35
20	Cast/prepare a spell 1 level higher than highest possible slot	15 + spell level
25	Cast/prepare a spell 2 levels higher than highest possible slot	25 + spell level
30	Cast/prepare a spell 3 levels higher than highest possible slot	35 + spell level

So, let's say Fazzle Bandazzle the Great (Sor 5) wants to cast a fireball, but he has no slots left. His Concentration check DC is 15 plus five times the spell's level, so he has to beat a DC 30. Now, if Nort the Mysterious (Wiz 3) wants to prepare a lightning bolt, but he's not high enough in level, he can still try to force the spell into his head with a Concentration check equal to 15 plus five times the difference between his highest possible level spell (2nd) and the spell he wants to cast (3rd), so his check DC is 20.

These attempts are not without their risks! If either of them fail, the attempt doesn't work and they have to make a Fortitude save. The formula for this is simple, too.

Failure to cast/prepare a spell with no slots left: DC = 15 + (spell level x 10)

Failure to cast/prepare a spell higher than highest possible slot: DC = 15 + (10[spell level - highest possible slot level]).

If the Fortitude Save fails, consult the table below for some nasty side-effects. For one, the strain of stretching one's mind too far can be painful and strenuous. In addition, there could be a magical back-lash, physically harming the caster who failed to either prepare or cast the spell properly.

Fortitude Save DC missed by	Result
1-5	The caster suffers a severe headache and overwhelming fatigue. As a result, he or she suffers a -1 penalty to all skill and ability checks, attack rolls, and saves. He or she recovers when able to rest for at least six hours.
6-10	The caster suffers headache and fatigue resulting in a -2 penalty on all rolls. He or she also takes 1d6 points of damage and cannot attempt to prepare or cast more spells than his or her level permits until he or she gets six hours of rest.
11-15	The caster suffers headache and fatigue resulting in a -3 penalty on all rolls. He or she also takes 2d6 points of damage and cannot prepare or cast spells at all for 24 hours.
16-20	The caster suffers headache and fatigue resulting in a -4 penalty on all rolls. He or she also takes 3d6 points of damage and cannot prepare or cast any spells at all for 48 hours.
21-25	The caster suffers headache and fatigue resulting in a -5 penalty on all rolls. He or she also takes 4d6 points of damage and cannot prepare or cast any spells at all for two weeks.
25+	The caster is burned out entirely—completely unable to prepare or cast spells ever again. In addition, he or she suffers headache and fatigue resulting in a -6 penalty on all rolls and takes 4d6 points of damage.

Some DMs may opt to change some of the side-effects, for example, adding temporary or permanent damage to the character's Intelligence. The character may also acquire some sort of curse or insanity. The DM is encouraged to be creative with some of the penalties for failure. Doing this sort of thing has to be risky.