Will

Philosophy:
Crippling magic, mind control, poisoned arrows--all of these things are a staple of fantasy gaming. Different games have handled the applications of these effects differently. In AD&D, we had the saving throw--at low levels, you were unlikely to succeed, but the consequences tended to be tame (except for save or die poisons, which I'll address later), and at later levels, success was essentially guaranteed, but the stakes were quite high with frequent disintegrates, death rays, magic jars, etc.

In 4th edition, these types of effects tend to target one of three defenses. As one gets higher in levels, the effects become more crippling (including stun spam), but, as opposed to AD&D, the chances of them hitting the players actually grow. This is awful!

So, I've designed the Will defense as a general resistance to all special effects. I have tied its value to Arcana as a boon for the Mage (TBR) and to give the attribute some cross-class appeal. Rather than having different will values for different affects, there is only one Will score, preventing the risk of a particular defense falling behind.

Will:
When an attack imposes a crippling effect on a player or an opponent, instead of or in addition to damage, the attack roll is not compared to AC. Instead, it is compared to Will. A character's Will represents their ability to avoid extreme danger, the blessing of the Gods, the power of their soul, their luck, etc.

Your Will score is equal to 15 + Arcana. Each time your character levels up, your score improves by one.

Errata:
The original posts for the Templar and the Warrior will be changed, but note that the Templar receives a +2 bonus to Will against Fear attacks and the Warrior receives a +2 bonus to Will against forced movement attacks.