Spell Contests
These rules cover generic spell casting contests that might happen in front of an audience. These rules do not cover Spell Duels between two magic using opponents confronting each other.
When a Spell Casting Contest is held at a festival it is typically between several traveling mages, priests, bards, or perhaps a witch and or hedge wizard.
The game mechanic is different than the standard opposed skill check.
First the reaction adjustment of the spell caster is used. Then the level of the spell minus one is added to this. The DM will assign an additional bonus of plus one to three based on the roleplay description of the spell cast.
This total is subtracted from a D20 roll made for an appearance check.
The participant who has the lowest number that is successful is the winner.
If Waldor has an appearance score of 12 (reaction adjustment of +0), casts a 2nd level spell (2-1=+1), and has an average roleplay description (+2) he will subtract that total (+3) from his roll of 14 for a final number of 11. This is a success, and if no other participant rolls under an 11 he will be declared the winner.
There are additional modifiers that might apply depending on the participant.
A bonus of +1 or +2 per appropriate non-weapon proficiency skill if the player can make the argument that it applies in the casting of the spell (such as Dancing seductively while casting a Charm spell).
For those who use Illusion spells in these contests there is an additional modifier based on how successful the audience is deceived. For every 5% of the crowd that fails their save versus spell the illusion is at a +1. However for every 5% of the crowd that succeeds in their save versus spell the illusion is at a -2. (Normal rounding applies)
If Tilpaf casts a 2nd level illusion spell that 80% of the crowd believes in (fails their save) she would get a +8 (+16 for those that failed, -8 for those that succeeded) to her appearance check.
Most spell contests will take place over 2 or more rounds with no chance for the spell caster to recover spells in between rounds.