I Put a Spell on You
Multiclassing and magic rests in the concept that there is an uneven spread of ability scores within spellcasting. Wizard is the only base class that relies on Intelligence as a modifier, while the Arcane Trickster and Eldritch Knight Archetypes both utilize Intelligence. Charisma has the highest spread, home to Bard, Paladin, Sorcerer, and Warlock. Cleric, Druid, and Ranger all share Wisdom. This is not a problem for spells like Invisibility and Shield that do not rely on a spell attack modifier or save DC. However, in order for a multiclass character to work using the same ability score, the only combinations possible are any of the same group that I have just listed. So if you want to play something similar to Ultimate Magus from 3.5, you need to take levels in Sorcerer and in Wizard. However, you’ll find yourself being torn apart by Multiple Ability Dependency or MAD. If your spell DC and spell attack roll are different for different spells, it requires a lot more book keeping. This is contrary to the more streamlined nature of 5e.
Within the fiction of the game it creates a very strange discrepancy once you start multiclassing. Let’s examine this idea. Wizards have studied formulas and rules of magic when the cast a spell they are using their intellect like executing a program on a computer. However when a sorcerer casts a spell they are essentially lashing out with their force of will. So if a sorcerer casts burning hands using somatic and verbal components, a wizard recognizes this. Can we rewind that for a second? A sorcerer needs to use somatic and verbal components, part of the wizard blueprint right? Seeing as wizards view magic as a science and are being smart (INT) about it, why on earth does a sorcerer use or need somatic and verbal components? Though through metamagic, sorcerers can use their powers to manipulate this spell and possibly avoid the use of verbal and somatic components. Sadly, this is the nebulous concept of magic that we are working with.
Though if a wizard takes levels in sorcerer, he suddenly starts having particular spells memorized and begins being able to manipulate spells through an innate magical talent. As a design note for 5e, I liked that sorcerers got metamagics as their own class ability, however the idea from 3.5 that metamagics were more of a modification that could be applied by any spellcaster gave a more concrete representation to the concept of magic in D&D. It insinuated that magic was a force that could be manipulated. D&D 5e is not an open system. Characters are defined by skills sets, and those skill sets develop at the same rate in the same style as other people of the same skill set. This is not a reflection of reality but a representation simplified for the sake of balancing a game. The system is not designed for “unique” characters with “unique” abilities. In 3.5 multiclassing was more of a challenge and even more difficult when it applied to spellcasters. In D&D 5e at least spell slots are conjoined in a way that it eliminates so certain degree of book keeping. Though it still causes that MAD dependence. In reality we tend to scaffold our abilities and learning via heuristics and algorithms, which suggests that when we learn something we will usually learn new concepts utilizing our previous knowledge to master the new concept. So when it applies to multiclassing, how do we reconcile the abilities of certain unique spellcasters in particular that are these unique cases?
Do You Believe in Magic?
Multiclassing in 5e came with ability score requirements which I really like. I hated the expansive fustercluck that was the plethora of classes in 3.5. Aside from prestige classes, base classes had no requirement other than the horrifically arbitrary alignment requirements, which 5e did away with. So in the case of our multiclass spellcasters, the requirements tend to necessitate a requirement of 13 in the class’s spellcasting ability score. In the case of Ranger and Paladin a physical ability score must also be met. Though keeping track of a DC of 15 for a spell and a DC of 18 for a different spell is obnoxious. It discourages multiclassing, which only discourages creativity outside a particular boundary.
To fix this we can implement the following addendum to the existing multiclass spell casting rules. As it exists now, as you cast a spell that you gained from a class that uses Charisma as the spellcasting modifier, you have to use that DC/spell attack modifier and the appropriate casting focus should you be using one (Suggests multiclass characters should resign themselves to material components. Start pinching that bat guano). Then for your Wisdom spellcasting class you use the figures and foci for that class. You also learn spells according to class progression.
I propose the following house rule:
“Each spell you know and prepare is associated with one of your classes and you use the spellcasting ability of that class when you cast the spell, unless the spell you cast is found on both class lists then you may use the spell casting ability score of your choice. The same applies for your spellcasting focus, should you use one.”
There are, of course, spells that classes share, and unique spells to each class. This goes back to the idea that sources of magic and the forms of magic are different. Sure, maybe you learned to cast spells through a piccolo before, but maybe you’ve moved on and since you know how to cast through a wand you would prefer to do that. Or maybe, you’d like to cast power word kill while playing a cello?
The core concept rests in the idea that multiclass characters break the mold. They are naturally more versatile individuals. The stiff rules tend to take that away. It makes sense that you would learn spells at the same rate, and even have them memorized permanently as part of your new training, but having to rotate between a clump of leaves, and a violin doesn’t make sense unless it is truly something that the other class’s training wouldn’t understand. It is reasonable sorcerers and wizards can cast fireball, but sorcerers may not have the same finesse and technical skill it takes to cast grease. Maybe the sorcerer may get angry and confused to the point that he spontaneously fires Crisco out of his hands…