As a reaction, which you use when you are hit by an attack or missed by 4 or less that you can see or when you take force damage, an invisible barrier of magical force appears around you. Roll a d4 and add the result to your Defense until the start of your next turn, including against the triggering attack. You can do so after the roll but before any effects of the roll occur.

Additionally, you have resistance to force damage until the start of your next turn.

Augment

You can expend 1 additional mana to trigger the spell when a creature that you can touch or see within 10 meters is attacked. The attacked creature gains the benefits instead.