Signature Magic

Each wizard has a signature spell. This is built as under Powers with Magical(-10%), and it's generally something they can do without spending mana, although they may apply Costs FP to it. (In the hybrid D&D terminology, it's an SLA.) The point cost of a wizard's signature spell also determines their general magical power; the stronger their signature spell, the easier a time they have casting other spells. Thus if a wizard has multiple candidate abilities, use the most expensive, but one mighty signature spell is best.

The rest of a wizard's spells are derived from versions built elsewhere as under Powers; they aren't normally built with Costs FP, but they do need Requires IT Roll(-10%) and Magical(-10%). The level of such a spell is 20%, round up, of its SLA cost. The wizard doesn't actually take these spells as SLAs, but instead purchases their formulae as scrolls or spellbooks; this costs 10$ per level of the spell, plus the cost of the paper(one page-face per level).

For a powerful spell, greater than the wizard's signature spell in SLA cost, the base difficulty is the spell's SLA cost. For an equal or lesser spell, the base difficulty is the spell's level. To get the final difficulty, further modify it based on the SLA cost of their signature spell:

Signature Spell
At Least
Difficulty Mod
5pt×4
8pt×3
10pt×2
20pt×1
40pt×1/2
60pt×1/3
80pt×1/4
100pt×1/5
etc.etc.

The wizard must then spend [Difficulty] mana(generally FP or ER), and take a -[Difficulty] penalty on the IT+Talent roll to activate the spell.

The in-character use of a spell formula is unspecified; the rules generally assume the wizard must've read the formula and must have it in hand. This may naturally lead to spellbooks as massive tomes that keep a huge number of spells in hand, without having to leaf through them in combat. Adding some Takes Extra Time to all but signature spells could represent having to leaf through to and read the formula to cast the spell. Alternately, just write spells on the character sheet under inventory instead of advantages, and ignore the potential complexities.

A wizard can invent new spells; use the New Inventions rules, with a prototype being a functional(but likely buggy) spell formula.

Since these wizards will need lots of mana, investing in an ER can help, as can the 5pt for basic(0 Thresh/0 RR) threshold mana access. (This can then be improved for 5pt per +6 Thresh or +2 RR.)

Example: Sahiret wants to cast Convoke Shadows, a level 4 spell that would cost 20pt as an SLA. Her signature spell is Illusion(AOE: 8yd(+100%), Magical(-10%), 45), and she has IT: 13 and Magic Talent: +3. Convoke Shadows is cheaper than her signature spell, which is powerful enough for further ×1/2 difficulty, for a final difficulty of 2. Reaching into her bag to touch her spellbook, she spends 2 mana and rolls against (13+3-2=) 14. With a natural 11 she succeeds, blending into the shadows of the courtyard… in a way immune to the considerable disbelief power of the human-headed snakes on guard.