Matt318
2010-03-05, 08:35 AM
Hello all. I've been developing and occasionally playtesting with my group a Harry Potter D20 system. I am still revising the casting system to make it feel more like the books, while maintaining a very easy level of playability. Here is my current design with some different options at the end.
There are magical skills for casting such as Transfiguration, Charms, Defense, Dark Arts, Divination, etc.
The skills are calculated as ability modifier + character level + d20 + trained bonus (trained = +5)
Defenses are similarly calculated as 10 + character level + ability modifer + class bonus
Casting a spell means that you roll your appropriate skill vs the defense of the target if applicable, if you overcome their defense, the spell takes effect. Some spells have effects even if you miss their defense such as Confringo (like fireball without the fire)
I also use "saving throws" which are like defense, but you roll a D20 in place of the static 10, for situations like ongoing spell effects where your trying to resist an effect, or if you drank a potion you didn't want to etc. (example, A dark wizard casts Crucio on a character, and overcomes the target's fortitude defense, so the spell begins (it is a spell that lasts for concentration up to 1 round per level). The second round he doesn't need to roll any more Dark Arts checks, just use his standard action to keep the spell active, while the target is now entitled to a Fortitude saving throw against the original Dark Arts roll made by the caster to resist and end the effect.)
Spells are classified as levels 1 - 9 for ease of transition of using D&D spells in the system. In game they are titled instead of numbered (basic, beginner, intermediate, OWL, NEWT, advanced, complex, rare, old magic). Each level has a Learn DC attributed to it (10, 15, 19, 22, 25, 28, 31, 35, 40). If you try to cast a spell you've never cast before, you must compare your skill result to this DC in addition to overcoming the target's defense (if applicable). There is also a table that allows for partial results or spectacular backfires depending on how much you miss the Learn DC of the spell by.
A character who could take 10 and pass the DC of a spell, no longer needs to check against the learn DC when they cast the spell because they have "mastered it". This does not mean that they are taking 10 it simply removes the check against the DC of the spell, so that they could roll below a 10 and have the spell work (although probably wouldn't get through the target's defense anyway if it was an offensive type spell).
Vitality and wound points system are used. Healing magic can repair wound damage but not vitality damage. Vitality comes back at a rate of your level per hour. All characters have a second wind ability to regain some vitality in emergency situations once per day, with a feat allowing it another time, and a talent in the Gryffindor class allowing it another. In addition, the Hufflepuff class has a talent that allows them to heal an ally who is below half some vitality once per encounter.
Here is the part that has been argued in play testing and I have waffled on as to what to do for design.
Casting a spell costs vitality equal to its level. Thus casting simple light charm on your wand costs 1 vitality, while an explosion would cost 5 vitality. Metamagic feats (casting a spell silently, casting a spell without a wand, etc.) multiply the cost by an amount. Silent spell multiplies the cost by x2 for example. One wand core (unicorn hair) reduces the cost of a spell by one vitality to a minimum of 1.
Arguments from my play test against this method is that it could lead to situations where characters can't cast spells because they are tired. This is never shown in the books or movies as being a limitation on magic. Also players feel that using the same pool that are considered "hit points" means that they are encouraged to not use magic so that they will be able to take a hit instead. Alternative to the last point...
Spells don't cost any vitality to cast unless your trying to cast a spell you haven't mastered and miss the Learn DC. The table for missing the spell now means that if you fail by 5 or less, the spell still might work but will cost you some vitality to cast it. For instance Harry trying to cast a patronus charm which is beyond what he should be able to do in his 3rd year and in the books it is described as draining his energy to keep his Patronus active while in later years there is no draining effect described. Metamagic feats will alter a spell's DC by a certain amount. For example if you are casting Expelliarmus, the normal DC is 19 to cast it. A character whose Defense skill score is +10 is said to have mastered this spell, and doesn't need to worry about beating a 19 on his roll anymore (because by taking 10 he would have gotten a 20). If he wanted to cast the spell silently (and had the silent spell feat), the DC would be increased by 5 to a 24. He is now must check against the DC of the spell, costing him some vitality if he fails by a little or not having the spell work at all if he fails by alot.
Well that's the casting system. Please give me your feedback! Thanks. :smallsmile:
There are magical skills for casting such as Transfiguration, Charms, Defense, Dark Arts, Divination, etc.
The skills are calculated as ability modifier + character level + d20 + trained bonus (trained = +5)
Defenses are similarly calculated as 10 + character level + ability modifer + class bonus
Casting a spell means that you roll your appropriate skill vs the defense of the target if applicable, if you overcome their defense, the spell takes effect. Some spells have effects even if you miss their defense such as Confringo (like fireball without the fire)
I also use "saving throws" which are like defense, but you roll a D20 in place of the static 10, for situations like ongoing spell effects where your trying to resist an effect, or if you drank a potion you didn't want to etc. (example, A dark wizard casts Crucio on a character, and overcomes the target's fortitude defense, so the spell begins (it is a spell that lasts for concentration up to 1 round per level). The second round he doesn't need to roll any more Dark Arts checks, just use his standard action to keep the spell active, while the target is now entitled to a Fortitude saving throw against the original Dark Arts roll made by the caster to resist and end the effect.)
Spells are classified as levels 1 - 9 for ease of transition of using D&D spells in the system. In game they are titled instead of numbered (basic, beginner, intermediate, OWL, NEWT, advanced, complex, rare, old magic). Each level has a Learn DC attributed to it (10, 15, 19, 22, 25, 28, 31, 35, 40). If you try to cast a spell you've never cast before, you must compare your skill result to this DC in addition to overcoming the target's defense (if applicable). There is also a table that allows for partial results or spectacular backfires depending on how much you miss the Learn DC of the spell by.
A character who could take 10 and pass the DC of a spell, no longer needs to check against the learn DC when they cast the spell because they have "mastered it". This does not mean that they are taking 10 it simply removes the check against the DC of the spell, so that they could roll below a 10 and have the spell work (although probably wouldn't get through the target's defense anyway if it was an offensive type spell).
Vitality and wound points system are used. Healing magic can repair wound damage but not vitality damage. Vitality comes back at a rate of your level per hour. All characters have a second wind ability to regain some vitality in emergency situations once per day, with a feat allowing it another time, and a talent in the Gryffindor class allowing it another. In addition, the Hufflepuff class has a talent that allows them to heal an ally who is below half some vitality once per encounter.
Here is the part that has been argued in play testing and I have waffled on as to what to do for design.
Casting a spell costs vitality equal to its level. Thus casting simple light charm on your wand costs 1 vitality, while an explosion would cost 5 vitality. Metamagic feats (casting a spell silently, casting a spell without a wand, etc.) multiply the cost by an amount. Silent spell multiplies the cost by x2 for example. One wand core (unicorn hair) reduces the cost of a spell by one vitality to a minimum of 1.
Arguments from my play test against this method is that it could lead to situations where characters can't cast spells because they are tired. This is never shown in the books or movies as being a limitation on magic. Also players feel that using the same pool that are considered "hit points" means that they are encouraged to not use magic so that they will be able to take a hit instead. Alternative to the last point...
Spells don't cost any vitality to cast unless your trying to cast a spell you haven't mastered and miss the Learn DC. The table for missing the spell now means that if you fail by 5 or less, the spell still might work but will cost you some vitality to cast it. For instance Harry trying to cast a patronus charm which is beyond what he should be able to do in his 3rd year and in the books it is described as draining his energy to keep his Patronus active while in later years there is no draining effect described. Metamagic feats will alter a spell's DC by a certain amount. For example if you are casting Expelliarmus, the normal DC is 19 to cast it. A character whose Defense skill score is +10 is said to have mastered this spell, and doesn't need to worry about beating a 19 on his roll anymore (because by taking 10 he would have gotten a 20). If he wanted to cast the spell silently (and had the silent spell feat), the DC would be increased by 5 to a 24. He is now must check against the DC of the spell, costing him some vitality if he fails by a little or not having the spell work at all if he fails by alot.
Well that's the casting system. Please give me your feedback! Thanks. :smallsmile: