Type of Feat: Special
Specifics: This power, bestowed by the Ritual of Purification, creates an immobile 5' wide cylinder of light that lasts for four seconds. Any undead or outsider that enters into the cylinder of light suffers 1 point of fire damage per character level of the caster per second. If any victim of this power is also within the area of effect of the Web of Purity, the damage of the Cleansing Nova is applied to all victims of that same Web of Purity.
Use: Selected. This feat can be used once a day.
This ability works differently than described:
1) The radius is 5 metres, not 5 feet, meaning it's actually a 15 feet radius. The shape is a sphere, not a cylinder. Also, what is not mentioned in the description, is the range of this spell, which is Medium (20 metres).
2) The spell does not create a persistent AoE, it's an instant spell that simply lasts for several rounds, similar to Vitriolic Sphere, so enemies entering the area AFTER the spell is cast are not affected (unless they have the Web of Purity effect, in which case they will be affected whether in the area or not, but they must be already affected by the Web of Purity at the time when Cleansing Nova is cast).
3) This ability is subject to spell resistance.