Penetrating Spell

Regular 
This spell is cast on another damage-dealing spell, granting it an Armor Divisor. The spells are cast one after the other, with no delays between castings. Penetrating Spell is cast first, and counts as a spell “on” for determining the effective skill for the second spell. 
A spell fortified with Penetrating Spell does not do extra damage to unarmored foes. Hardened DR defends against the armor divisor conferred by this spell as normal.

Duration: Until the second spell expires. 
Cost: See table below.