Spontaneous Casting

Magic is great and mysterious source of power. The typical paths of magic teach the casting of specific spells which a caster can cast a certain number of times safely. This is the safest and most teachable school of thought, but it is a limitation to the true power of magic. Spellcasters with enough skills may tap into this power to alter their spells or create new effects. Though the risks of spontaneous magic are great so are the rewards.

Overview
Sometimes the magic granted to a spellcaster just isn’t enough. Though there are various ways to alter spells, and spontaneously cast the basic process remains the same. Three skill checks are required to alter magical energies. Knowledge(Arcana) for arcane casters or Knowledge(Religion) for divine casters provide the theoretical background for the casting. Spellcraft is the central skill required in shaping the magical energies. Finally Concentration is required as the energies must be held in place while the casting is done. A spellcaster may never take 10 or 20 on these checks. Also any skill boosting items or magic are not taken into effect for the purpose of these checks.

If these three checks are successful then so is the spell. The character gets the expected effect at full power. The desired effect must be fully described by the player in advance.

If two of the three checks are successful than the spell succeeds, but all numerical values other than the save dc are halved. This includes(but is not limited to) damage, area, range, duration, and bonuses. If no such values are applicable, the save dc is halved, as is the caster level for determining spell penetration.

If only one of the the three checks succeeds, the spell fails. The caster managed to control just enough energy to avoid disaster.

If all three checks fail, the magical matrix is somehow perverted or reversed, resulting in backfire. The spell is turned against the caster. This can result in a number of malicious effects which can either harm the caster’s group or aid enemies. The exact effect(s) of backfire depend greatly on the specific spell and is at the discretion of the DM.

Spontaneous casting can be done either on the fly or as a ritual. Casting on the fly is more difficult and requires two full-round actions. Ritual casting takes 10 minutes. Unless otherwise noted casting as a ritual reduces the the skill check DC by 5. During a ritual the DC may be further reduced by using expensive or powerful material components. Generally speaking 200 gp worth will reduce the DC by 1, to a maximum of 5. Special or powerful components may produce more potent benefits.

What ever effect a caster is trying to produce the cost for the spell must be paid. This can be done through expending spell slots or blood burn. Special bonus slots from specialization or domains may only be used to power spells in the same school or domain.

Change Type Base DC
Overcasting 25 + (2 x Spell Level)
Unprepared Spell 25 + (2 x Spell Level)
Unraveling 20 + Spell Level
Spell Burn 25 + Spell Level
Blood Burn 25 + Spell Level
Freeform Casting 35 + (2 x Spell Level)
Freeform Casting(Ritual) 30 + Spell Level
Spell Alteration
Decrease Power 15 + Spell Level
Increase Power 25 + Spell Level + (2 x Metamagic Cost)
Substitute Spell
Same School and Type 20 + Spell Level
Same School and Type(Lower) 20 + Final Spell Level
Same School and Type(Higher) 25 + Final Spell Level
Same School or Type 25 + (1.5 x Spell Level)

Overcasting
It can be frustrating needing a spell a caster has access to but can’t cast because it is too high level. Overcasting is the process of attempting to cast a spell the caster knows, but can not usually ready or cast due to level or ability score.
The caster must spend spell slots totaling the spell level he wishes to use. When casting On the Fly every spell slot burned increases the DC by 1. During Ritual casting the caster may freely burn slots from any level without penalty.

Unprepared Spells
This option is available when a caster needs a spell he can normally cast, but did not ready that day. He must burn a spell slot of the same level.

Unraveling
A caster can attempt to unravel a readied spell and turn it into raw power to blast their foes. The unraveled spell does 1d6 damage per level as a ray that extends to close range(25ft + 5/2 levels). The caster caster must make a ranged touch against the target who receives a fortitude save for half damage. This effect is not subject to spell resistance.

Spell Burn
Spell Burn is the process of powering a spell the caster has readied that day with lower level spell slots. The spells must be from the same school. On the Fly the DC increases by 1 for every slot burned.

Blood Burn
Sometimes a caster finds them self in dire need of the ability to cast more spells even though they have used all their spell slots for the day. In this case a caster may reach deep inside himself and power their spells with their very life force. A caster may inflict themselves with 5 points of damage per spell level to cast a spell they have readied that day with out consuming any spell slots. This damage must be taken whether the spell succeeds or not and it can not be healed through natural healing. Casting spells in this way is extremely risky and a backfire while blood burning is even more dangerous than normal(most likely this will translate to ability damage on top of the normal backfire). Attempting to use blood burn to power other types of spontaneous casting increases the DC by 5 + 1 per spell level and risks the more severe backfire.

Freeform Casting
The most skilled Spellcasters can spontaneously manipulate the very building blocks of magic to create new effects not outlined by tradition spells. This is freeform casting.
Note from the DM: The guidelines for freeform casting are long enough that I really don’t want to type them up on here. If this is something that interests you talk to me and I will point you towards the relevant book.

Spontaneous Casting

House of the Magus TheNeonKnight