Modifying spell components to add flavor

Question

One of my player's character is playing a tiefling wizard (evil party). He asked me if he could modify the spells components to add flavor and narrative uniqueness.

I said yes, of course, and we briefly talked about the options. Now, I'd like to do my homework and figure out if there's something already written or if I should just make it all up (and keep track of it).

So far I've classified those modifications somewhat like this:

1. By appearance - The tiefling casts a magic missile, but instead of a few bright magical bolts, a few spheres of black ooze dart from his fingers and/or the air is filled with a foul stench. Stuff like that.
2. By energy type - This is pretty much the High Arcana lore from the Archmage prestige class or the Energy Substitution feat (thanks Miniman), which allows to alter the element (fire, cold, electricity, sonic, acid) of any spell. But for balance's sake, I guess I'd have to make it costly. That and the fact that he'd have to research a single spell for weeks, to figure out how to modify it.
3. Metamagic - For this I could use the metamagic components rule in Unearthed Arcana.
4. And while at it, I should also mention: Research new spells - This is quite simple, since I can use the guidelines in the DMG.

Since 3 and 4 are pretty well covered, I'm mostly interested in the first two options.

I'm expecting him to:

• Do some research (access to library required).
• Experiment with different components. Ie: use a pinch of boar's fur instead of (or along with) horse's fur to cast Mount.
• A combination of the above.

He's already excited about adding his own blood as a material component and "see what happens".

Is there something like this already written?

I should add that his original idea was just on point #1 above, but we drifted into the other options.

Answer 1

Are you sure you want to do this using spell components? Like, really, really sure? Spell component tracking can really slow down a game due to the extra item tracking and figuring out what to use to get what effect. There's a reason why the spell component pouch lets you by the rules handwave away almost all component tracking, after all.

If you are sure...

By appearance - Don't require cost/tracking

Spell appearance is primarily fluff, so you shouldn't spend a lot of effort coming up with component lists for what is required to make a plaid ray of enfeeblement. Those components likely won't cost anything anyway, so by RAW a spell component pouch would still let it be handwaved away. You could require explicit tracking of that stuff, but that's adding book keeping more than flavor.

It would probably be worth making him invest research time in character into figuring out how to do it, though. That could be done using something simple like a series of Spellcraft and/or Knowledge Arcana roles (DC 15 + spell level), and access to a library (a strictly in character RP requirement) in order to master a spell sufficiently to be able to modify it. Perhaps require a fee to use the library unless the PC has a reason to be allowed to access it (such as doing a favor for someone, or being noteworthy, etc)

Once a spell's appearance is mastered, just put a mark next to it on the PC's spellbook and let him modify at will.

The feat Spell Thematics lets you do something like this, but it also does some other things (boosts DC to identify spells when casting, lets you cast at a higher caster level), and costs a feat. For pure fluff, a feat is a very expensive price to pay.

For just wanting to shoot purple spells, there honestly isn't anything to gain by making the player pay significant amounts or keep a complicated list of components for it. I've never heard of anything written that does exactly what you want, so you may have to write up a full list of extra components yourself if you really want to track that level of detail. "Make it up as you go along" might be a solid approach there, as it's going to be a huge undertaking if you try to build the entire thing in advance and anticipate all the possible appearance changes to a spell that your player may want to make.

By energy type - Do Keep Track

Complete Mage has a list of components to modify spell effects already, and it's fairly reasonable. Given the added effectiveness this can have, these should have a cost and are worth tracking as items. There aren't any items on that list for changing energy types, but the system itself is solid.

So in this case, I'd use that system and simply add five new components - one for each energy type. I wouldn't set the cost over 50g, as higher level spells require multiple units in this system. Setting it too high would mean that the component cost would become comparable or even higher to a scroll cost of the same spell (a scroll of Fireball costs 375g, and could be written already substituted to Acid for no additional cost as Energy Substitution is a +0 Metamagic).

Metamagic - Unearthed Arcana

Already mentioned. :) It works, but it can get pricy.

Research New Spells

In addition to the DMG rules, there were also third party rules for this written in The Quintissential Wizard II. I have never used them in an actual game, so can't vouch for how good they are. But they exist if you're interested in alternatives.

Answer 2

There was a set of Spell components featured in the book "Complete Mage" which increased the power or changed the effects of spells when used as part of a casting of a normal spell, you could use the list as sort of a guideline for how you should homebrew your spell components for this tieflings spells, the list of components itself is located on Pg. 135, or in Unearthed Arcana. Which I believe you have already posted.

If you are going to write homebrew I would definitely insure that you keep to the following set of guidelines.

Base your homebrew on existing items and effects.

Try to find items which emulate the effect that you're looking to create and look for an approximate value for the effect you're going to be copying. If you don't make an attempt in this area you could be sailing into dangerous waters, as homebrewing without some sort of in-game guidelines in this instance would typically lead to a really overpowered Wizard.

Don't require feats for fluff.

In the instance of changing spells By Appearance no feat should be required in changing the spells ever so slightly to change the way the spell looks. Each spellcaster may have a different way of casting a spell that creates a different looking effect. In the example you used with Magic missiles becoming Foul smelling Ooze bolts, it would be a purely cosmetic effect and wouldn't change much as far as the spell effect is concerned.

The missiles could just as easily become roaring dragons, small bolts of crackling lightning, Unerring green magical arrows, Screeching phoenixes, or the like by changing the spell components to dragon scales, a crystal rod and a felt pad, a small archery target, or a phoenix feather. Fluff should be fluff, don't make it cost extra. You can use the components of similar spells ( like bat guano for fireball ) to make other spells take on the appearance of small fireballs, like I did with the above spells ( Which were Lightning bolt, True strike, Phoenix Fire, etc. )

For the second one, By Energy Type a feat already exists for swapping out a spell with a different elemental subtype, Energy Substitution.

Choose one type of energy (acid, cold, electricity, or fire). You can then modify any spell with an energy descriptor to use the chosen type of energy instead. An energy substituted spell uses a spell slot of the spell's normal level. The spell's descriptor changes to the new energy type—for example, a fireball composed of cold energy is an evocation [cold] spell.

As far as Metamagic is concerned I believe you're on the right track of creating your own components if you use those as a guideline, and making new spells is quite a simple task if you base the spells you're making on existing spells (like your magic missile example) Remember that Wizards are already very cheesy so you don't want to go too far in modifying spells beyond their similar PHB counterparts.