[peterb]

This post outlines two methods of incorporating spells that are originally designed to be used with the d20 game system into BRP/d100 games. Since there are a lot of material published for d20 and some of it is quite useful a conversion method could be quite handy - IMHO. The following is just a bare bone set of rules, I haven't even decided for my self which of these alternatives I like the best.

Method 1: Skill based system

• Each school of magic is a separate skill.
• Spells need not be memorized.
• Spells can be cast from books, at double the casting time.
• Each spell has a difficulty rating of 0 to 45 which is subtracted from the school skill level (d20 spell level x 5).
• Spells costs 1 mp per two d20 spell levels, rounded up, to cast. Thus 0-1:st lvl = 1 mp, 2 -3:rd lvl = 2 mp’s, etc.
• Spells can be manipulated by expending more magic points. Each expansion of area, range, duration or additional targets or missiles costs 1 magic points each. Example: by default the spell magic missile creates one magic missile, adding three extra missiles costs three additional magic points, for a total cost of 4 mp’s.
• A wizard can only manipulate an amount of magic points equal to school skill level / 10 (rounded to nearest whole number) at any given time. Example: a wizard with a skill of 63 can only manipulate 6 magic points. He couldn’t expand a fireball (a 2 mp spell) more than 4 points.
• Learning a spell is a two week task that has a chance of success equal to school skill – difficulty rating. A wizard with 55% skill would need to roll 40 or lower to learn the spell fireball (DR 15). A wizard may add a week to his studies and increase his chance of success by the average of his INT and POW (rounded to the nearest whole number) percentiles. Our wizard, with INT 14 and POW 15, could thus add 14 percentiles to his chance of learning the fireball spell.

Method 2: “Fire and Forget” system

• Casting a known, memorized, spell succeeds on a roll of 01-95. A 00 is still a fumble.
• Spells costs d20 spell level x 3 mp to cast.
• Expanding a spell costs 2 mp per expansion (see above).
• A wizard starts out with POW / 2 mp.
• Each 10 percentiles of skill in any spell school skill adds one mp.
• Learning a spell is a two week task that has a chance of success equal to school skill – difficulty rating. A wizard with 55% skill would need to roll 40 or lower to learn the spell fireball (DR 15). A wizard may add a week to his studies and increase his chance of success by the average of his INT and POW (rounded to the nearest whole number) percentiles. Our wizard, with INT 14 and POW 15, could thus add 14 percentiles to his chance of learning the fireball spell.

Method 2: “Fire and Forget” divine magic

• Casting a known, memorized, spell succeeds on a roll of 01-95. A 00 is still a fumble.
• Spells costs d20 spell level mp to cast.
• Expanding a spell costs 1 mp per expansion (see above).
• A Priest or Shaman has POW = mp.
• Spells are learned from Spell Spirits. Kult spirits normally has POW equal to (spell level + spell level d3). Normal Spell Spirits has POW equal to spell level d6. Example: a priest that wishes to learn a 2:nd level spell must fight with a spell spirit with POW 2d3+2. A shaman trying to learn the same spell must fight with a spell spirit with POW 2d6.