It’s Canon Now: You can coup de grace with a spell

Coup de grace is an interesting and rarely used rule – against monsters, reducing them to 0 hitpoints is usually enough to consider them “dead,” and against players, it’s a surefire way to make people mad. Despite this, it does occasionally come up.

The standard rule goes as follows:

As a full-round action, you can use a melee weapon to deliver a coup de grace (pronounced “coo day grahs”) to a helpless opponent. You can also use a bow or crossbow, provided you are adjacent to the target.

You automatically hit and score a critical hit. If the defender survives the damage, he must make a Fortitude save DC 10 + damage dealt) or die. A rogue also gets her extra sneak attack damage against a helpless opponent when delivering a coup de grace.

Delivering a coup de grace provokes attacks of opportunity from threatening opponents.

You can’t deliver a coup de grace against a creature that is immune to critical hits. You can deliver a coup de grace against a creature with total concealment, but doing this requires two consecutive full-round actions (one to “find” the creature once you’ve determined what square it’s in, and one to deliver the coup de grace).

The salient points of this rule are:

• Full round action
• Helpless opponent
• Auto crit
• Save or die

The difficult parts are that the rule specifies a melee weapon, or a bow/crossbow if the assailant is adjacent to the target (basically: gun to the head). Spells are not mentioned.

But…

Considering the proximity rule which allows bow weapons, it’s difficult to imagine that a spell that:

• Can be delivered as a standard action, or within one round
• Does damage, either direct or area of effect
  • conversely, that does not solely do conditional damage (eg Blindness/Deafness)
• Can be effectively critted.

Can’t be used for a coup de grace attack.