In an earlier post I sketched out a new system for magic in D&D 3.X. After having debated this with my wife, that system was abandoned in favour of something a little closer to Ars Magica. This has yet to be play-tested, but as it seems like the consensus may be leaning towards pulling the plug on LL, that may happen already next weekend.
Like the Craft, Knowledge, Perform, and Profession skills, this isn't a single, defined skill, but rather a group of skills that fall under the same category. Spellcraft is divided into the separate schools of magic. Thus, each time the magic-user purchases a rank in Spellcraft, he must specialise in one of the eight schools, Abjuration, Conjuration, Divination, Enchantment, Evocation, Illusion, Necromancy, or Transmutation.
To cast a spell, the magician must roll a successful Spellcraft (appropriate school of magic), DC 15 + level of spell, and expend Vitality Points equal to the level of the spell. While the highest level of spell she can safely cast is (arcane caster level / 2, rounded up), it is possible for a magician to cast any spell she has access to in written form. When casting a higher level spell, each level above her range incurs a -3 penalty to the casting roll. To determine the caster level of any spell, each 2 above the casting DC adds one level to the caster's arcane caster level.
Example: Our 6th level sorceress is attempting to cast Control Undead, a 7th lvl Necromancy spell from a scroll. She has a skill modifier of 15 in Spellcraft (Necromancy). Her casting range is 3 (6th level / 2). Control Undead gives her a -12 penalty ((spell level 7 – casting range 3) x 3). To successfully cast the spell she needs to match DC 22 (15 + spell level). Her player rolls a 19, and with a +3 modifier (skill 15 – 12 penalty = 3), and so our sorceress is successful her casting. Her caster level is 6.
Unless casting from a written source (see below), the magic-user must memorise any spell she wishes to cast. The rules for memorising are the same as in the 3.5 RAW.
Spell Books and Scrolls
A magician may cast or memorise any spell he has access to, be it in a spell book or on a scroll. To read another magician's spell book, the magician must roll a Decipher Script check, DC 15 + level of scribe + Int modifier of scribe. Note that since stealing a magician's spell book is such a lucrative undertaking, most magicians will write their librams in code, and often put both magical and mundane traps on the book.
Copying a spell from another's spell book is costly and time consuming. The cost in materials is 100 gp per level of spell. It requires a Knowledge (Arcana) check, DC 15 + level of scribe, and takes 1 day per level of spell. If the roll fails, all invested time and money are lost, but she can always try again.
Studying a Spell
A magic-user may spend time and energy to study a spell, thereby gaining intimate insight and familiarity in the pattern and formulae of the magic. To study a spell, the magician must first have access to the spell in written form. She must then spend 7 days – Int modifier (minimum 1 day) per level of spell, and successfully roll a Spellcraft (relevant school of magic), DC 15 + spell level. If this roll is unsuccessful, all time is lost. If successful, she must spend 1 skill point per level of spell.
Once a spell has been studied, the magician gets a permanent +3 bonus to cast that spell.
Taking 10/Taking 20
You can take 10, but you may not take 20 on the spell casting checks. When taking 10, the casting time is three times that of what's listed in the spell's description.
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