How would you design a magic system for a Harry Potter style of play?

[DM-Rocco]

How would you disign a magic system for a Harry Potter style of play?

There is magic without wands and such, but it seems to be limited. So a wand focus, or maybe a staff or rod focus to update it into D&D is in order, but then what?

Would you design it more like Psionics with a pool of points, or a hit miss chance for each spells or a random effect chart like chaos magic?

What are your thoughts and ideas?

Spell craft checks for each spells?

To hit checks for each spell?

Obviously the wands strength gives the PC more or less power and a penalty of some sort would come into play it you aren't using your wand.

What do you think?

 

[Whizbang Dustyboots]

It's arcane magic, by definition.

It doesn't require preparation.

Spell-casters get access to a LARGE number of spells.

Wands are either required or make casting spells much, much easier. Maybe casting without one effectively lowers the ability score required to cast a spell by 5, so you'd need spell level + 5 in Intelligence to cast a spell without a wand, and you'd be limited to lower level spells, for the most part.

I'd probably use a spell point system or a per-encounter system for spells.

 

[SteelDraco]

The trouble with Harry Potter magic is that the subjects taught in school don't really map to mechanical effects very well, and we're not given any kind of underpinnings or explanation of what's going on. That makes it difficult to pick up any kind of mechanical basis from which to extrapolate a system.

For example, why are some things potions? Can you cast a charm that has the effect of drinking Veritaserum? How about Polyjuice Potion? Is there a reason for this difference? What differentiates charms from transfiguration?

That being said, if I was going to set up a Harry Potter game, I'd probably use the skill tricks mechanics from Complete Scoundrel, or something similar, combined with a Warlock-like Wizard class. None of the characters in the books ever get tired from casting spells, nor do they run out of any kind of magical energy. Different spells would have different levels of power, and you have to be a certain level to learn them. They would cost skill points, or some of the free 'spells known' points you get as part of being a Wizard. Spells would require skill checks, probably with some sort of backlash mechanic if you critically fail. You would be limited by the number of actions you have, rather than the number of spell slots per day; more powerful effects would require longer casting times, for example.

I'm not sure if I'd have different skills for different types of magic. Probably - it seems like there are different skills, after all, and not everyone's equally good with everything. The trick would be figuring out how to split it up. My tendency would be to use D&D schools, or something similar - differentiate by effect, rather than flavor. Defense Against the Dark Arts would mostly be Abjuration, with a few Conjuration effects (the Patronus, for example). Charms seems to be all over the place, but primarily Evocation and Enchantment. Divination seems to be not particularly useful. Transfiguration would get its own skill, I think.

There are thorns to this approach, but you could model the basic setting of HP fairly well with it, I think.

 

[Whizbang Dustyboots]

Mage: The Awakening or Star Wars Saga might be good systems to look at as well.

 

[Umbran]

My very first thought is to use a variant of White Wolf's Mage: the Ascension. I that game, there are already rules for "foci" that a character needs to perform specific workings. Strengthening that, and the game's idea of "rote casting" might yield the desired results.

 

[Whizbang Dustyboots]

My very first thought is to use a variant of White Wolf's Mage: the Ascension. I that game, there are already rules for "foci" that a character needs to perform specific workings. Strengthening that, and the game's idea of "rote casting" might yield the desired results.

Mage: The Awakening makes the rotes the primary way of spellcasting. Foci are also still in the system, and it would just require making them even more important.

 

[Jolly Giant]

I think you'd have to drop the Int requirement for casting spells (i.e. a wizard must have Int = 10 + spell level). High intelligence doesn't seem to be required for HP wizards, although the most intelligent ones are also the ones who learn the most spells. A wizard could perhaps start with a number of known spells equal to his total Spellcraft modifier (including Int, Skill Focus, etc).

There is apparently no limit to the number of spells you can cast in a day, but casting a spell seem to require a Concentration and/or Spellcraft check. There seem to be a great difference in the skill check DC from one spell level to the next, if there is such a thing as spell levels at all. If you use spell levels, the DC could perhaps be 10 + (spell level x3). If you don't use spell levels, you'd probably have to assign a DC to each spell. Failing the check by too many points might create undesired effects.

The vast majority of spells seem to require a ranged attack roll, unless you cast it on yourself.

Then there is the whole wand thing. Seems to me that casting spells without a wand bestows a severe penalty on the skill check(s), attack roll, save DC and effective caster level. Trying to use a broken wand bestows a slightly smaller penalty, and using somebody else's wand bestows an even smaller penalty. If the penalty to caster level brings you to caster level zero or less, you can not cast spells (the youngest (i.e. low-level) wizards seem unable to cast spells without a wand). Using a broken wand might also create unexpected results (the wand acting similar to a Rod of Wonder).

Just my 0.02$.

 

[lonesoldier]

Don't forget to remove everything in regards to Paradox!

(I only have experience with Mage: The Awakening, so I'll speak in terms of it). You'll have to do something about the Arcana, maybe rearrange them in terms of Potter-verse magic schools? (Charms, Transfiguration, etc)

As for rotes, there's a nice list here.

 

[Vorput]

Spells in Harry Potter seem most equivalent (if I can find a d20 equivalent) to a Warlocks invocations. It seems once you know a spell, generally, you can cast it as much as you want.

The question then becomes how you learn spells, and how many said spells you can 'know.' (Probably intelligence based)

Theres also the issue that some characters seem better at casting spells than others... (not really sure how you'd represent this).
Edit: Perhaps putting points into a skill-like ability that applies to your spells under categories such as Charms, Transfiguration, Divination, etc.


I agree with the poster who mentioned ranged attack rolls though, A good dexterity would be a huge asset in the Harry potter world (to both aim, and avoid incoming, spells).

 

[blargney the second]

I'd go with a d20 Star Wars Force system.
-blarg