Shield

Close-quarters spell
Recharge, 11+ after battle
Action: 
Free action to cast, when an attack hits your AC.
Effect: 

The attacker must reroll the attack. You must accept the new result.

3rd Level Spell: 
You gain a +2 AC bonus against the rerolled attack.
5th Level Spell: 
You can also use the spell against attacks that target your Physical Defense; replace references to AC with PD.
7th Level Spell: 
The bonus to AC/PD on the rerolled attack increases to +4.
9th Level Spell: 
The bonus to AC/PD on the rerolled attack increases to +6.
Adventurer Feat: 

You can now choose either of the attack rolls, in case the second one crits or is otherwise bad for you.

Champion Feat: 

Recharge roll after battle is now 6+.

Epic Feat: 

Hit or miss, you take only half damage from any attack you use shield against.