It is possible for casters to cast certain spells they know in ways that far surpass their parameters normally. This, however, is not done lightly, and is very costly.
In order to cast an Amplified Spell, certain conditions must be met.
First, each caster must have the [Amplified Spell] feat. Additionally, one caster in the circle must have the metamagic feat that creates the desired effect.
Secondly, this cannot be done with a single spell caster. Depending on the desired effect, you must gather up to seven more spell casters to aid in the spell casting, each of the same type. (Mixing divine casting together with arcane casting has unpredictable consequences.) Each must have the spell prepared or know it.
Thirdly, the casting time is greatly increased. Typical amplified casting takes around ten minutes to complete. Some more complex or higher level spells can take much longer.
Fourthly, any material costs are required of each spellcaster. While this isn’t a major factor when it comes to some mundane material components, some may find it difficult to find eight 5000gp diamonds for an advanced spell. If the spell has an XP requirement, each spellcaster must contribute.
Lastly, casting an Amplified spell is incredibly taxing. Aiding in an Amplified spell drains each of the spellcaster’s remaining spells per day, and also drains their spells per day for the next 1d4 days.
Due to the nature of the ritual, there is a very large amount of magical energy circulating between the casters. If any of the casters fails a Concentration check to avoid losing a spell, that caster takes an amount of damage equal to 1d12 per combined caster level. The remaining casters take damage equal to the damage taken by the first caster divided by the number of casters remaining in the circle. The amplified spell is not lost until only one caster remains.
However, despite all the costs, casting an Amplified Spell has the following effects:
- If the spell has a duration longer than instantaneous, the duration can be multiplied by several factors.
- If the spell has an area of effect, the area may be expanded by a factor of 5 for each spellcaster involved.
- If the spell has a damage component, the damage increases to the combined caster level of each spellcaster involved.
Spells able to be amplified in this way are very limited in number.