D&D 5E The Nature of the Shield Spell

[Storyteller Hero]

There was a debate on Facebook about how the Shield spell works and what it looks like. I thought that it would be worth sharing in forum.

The Shield spell grants a +5 bonus to AC, cast when you are hit by an attack.

According to Sage Advice, the caster should know the roll made for the attack before casting Shield.

https://www.sageadvice.eu/2014/10/11/shield-before/

There were some that argued that the caster should not know the roll and should cast Shield before seeing if the spell would block the attack or not, because it was metagaming too much to know the roll.

The counter argument was that if the caster was able to cast Shield in time (the moment before impact, before damage can be rolled), then the barrier of force created by the spell would block the attack, so if the attack was going to hit anyway, the caster would not have had the chance to cast the spell in the first place before getting hit.

This brought up a question of whether Shield was a surrounding forcefield that could be broken through or if it was something more like a big floating shield made of force that positioned itself to block attacks.

It was argued for the floating shield opinion that Shield gave a bonus to AC instead of temporary hit points like the abjuration wizard archetype feature Arcane Ward, so it wasn't something destructible.

It was also argued for the floating shield opinion that the Shield spell does not protect from area effects, so it couldn't be a surrounding field that covered the body from head to toe.

The counter argument about the lack of protection from area effects was that the Shield Master feat allows a character to use a shield to defend against area effects. The counter argument was itself countered by a statement that a feat could be made to do the same for the Shield spell, and that if it takes a feat to make a worn shield or Shield spell to protect from an area effect, then neither would normally have an effect that covered the whole body at all times.

Mage Armor was mentioned as a surrounding effect that granted AC instead of temporary hit points, but that was countered by the argument that Mage Armor might surround, but it does not necessarily envelop completely from head to toe; a belt surrounds the body but it doesn't cover everything. Mage Armor probably functions more like (though not exactly like) actual worn armor, which is why it can only be cast on a creature not wearing armor.

The debate ended there. What do you all think? How do you feel about this?

 

[lonelynoose]

Shield is a reaction, that's why you should know the roll. Basically, you know you're going to get hit, whether or not you take the damage is up to the caster. Something like, 'Oh sh*t, shield isn't going to work on that. OUCH!'

Also, since it lasts a round then I'd say it's a surrounding forcefield since an attack from the back would also have the +5.

 

[Storyteller Hero]

Also, since it lasts a round then I'd say it's a surrounding forcefield since an attack from the back would also have the +5.

If it's a floating shield that moves and turns to protect you, that could protect your back with the same AC bonus. The argument against surrounding field is that Shield doesn't block or even reduce area effects like Fireball.

 

[Hriston]

The spell just does what it says. It creates an invisible barrier that protects you specifically from attacks that target you and only interposes itself in a meaningful way when an attack occurs. So it operates pretty much just like a shield.

 

[Bardbarian]

well you cant cast the spell until the attack is a hit for starters. the only questio is wheter you know if it will turn the hit into a miss. I give the player that knowledge because they are using a limited resource (spell slot) to stop an often unlimited resource. attack roll. the player is trading a spell slot for HP that would otherwise be lost. This is the intent of the spell. 5e is designed under the intent that the number rolled is known by the players. there are several abilities that function under this rule, bards come to mind. If the players do not know the rolls on the dice then there are some mechanics that do not work. I personally roll in the open when DMing. DM screens were never meant to hide the dice, only for a point of quick reference and to hide maps and other statistics that are not open knowledge. If you do insist on hiding the rolls from your players then I suggest you do not use shield on your own NPCs because they will function under the knowledge of the rolls and therefore be using superior versions of the same spells.

 

[Bacon Bits]

Don't get caught up in how the abstraction of combat doesn't make sense. The dice rolls and spells represent what happens mechanically, but they exist because combat is too dynamic.

Mechanically, the attacker rolls the die and beats the Wizard's AC. The Wizard' player sees that his character's AC is beat, and decides to cast shield using his reaction action, and gains +5 AC. This turns a hit into a miss because reactions can happen before the event that they react to.

Story-wise, the Wizard sees an incoming attack and, knowing the attack could be deflected, raises a magical barrier to protect himself from an attack in a moment's notice.

This is what those video game analysis channels on YouTube would call ludonarrative dissonance. There is a difference between what happens in the story of the game from the perspective of the characters, and what happens with the mechanics of the game from the perspective of the players. Now, you could reduce the ludonarrative dissonance here by making shield into a spell that gives the spellcaster special foresight instead of creating a magical barrier, but that should also make it into a Divination spell instead of an Abjuration spell. That's kind of silly from a spell school design perspective because Abjuration should generally have the best defensive options, so that's not how the spell works.

Bottom line is: don't look too deeply into D&D's combat mechanics and expect to find a simulation. It's going to fall apart.

 

[Donnor80]

So, the spell says you spend your reaction when you are hit by an attack or magic missile. If you are not hit, assume the roll was below your AC. Otherwise, the player need not know the roll, keep some things left to the imagination!

 

[Storyteller Hero]

So, the spell says you spend your reaction when you are hit by an attack or magic missile. If you are not hit, assume the roll was below your AC. Otherwise, the player need not know the roll, keep some things left to the imagination!

The argument counter to that is that if you get hit even with Shield up, then you never cast Shield in the first place, because Shield would have blocked that hit, so there's no point in holding back the roll result.

 

[Lidgar]

You can explain whatever option you prefer with the right narrative.

In our group, we think of it as a shield made of force but is attuned to blocking targeted attacks (including magic missiles).

Being magic, when memorized or known, the caster has a 6th sense to determine if it can be used successfully to block an attack in a split second reaction.

Done.

 

[FesterJester]

Since 5e doesn't have facing, the idea of it needing to be a totally surrounding force field is unnecessary. As attacks come in the shield moves in order to intercept while its up.

As to the idea of it being a reaction, my previous DM explained it like this:
1. attacker swings at you
2. *rolls dice* yea, thats going to hit
3. player uses shield
4a. the hit misses
4b. the attacker either is quick and crafty enough to get around your last second protections or is strong enough to penetrate it or anticipated you using it (if they suspected you might) and was prepared for it.

No defense is impenetrable so the player need not know the roll, just that they have an much increased chance of avoiding damage with this spell. It sucks when it fails, but it sucks when somebody saves against your charm person spell too. Just because its a limited resource, doesn't mean its guaranteed.