16 Mar Shield 5e D&D Guide 
Shield might be one of the most popular and misused spells in the game. It provides a last-second defense for spell casters, and the aftereffects might be just as important. Shield has the power to change the outcome of a fight, and for a defensive spell, that is rather beneficial.
The rules for Shield are found in the Players Handbook on page 275.
Abjuration 1st Level
Casting Time: 1 Reaction
Components: V, S
Duration: 1 Round
An invisible barrier of magical force appears and protects you. Until the start of your next turn, you have a +5 bonus to AC, including against the triggering attack, and you take no damage from magic missile.
The rules for Shield reveal the spell as a reaction spell. This reaction is triggered when you are hit or targeted by Magic Missile. The spell increases your armor class as a reaction or after you know you have been hit. The armor class bonus carries through until the start of your next turn.
Is Shield Good?
Shield might be one of the best spells in the game. It blocks Magic Missile automatically, can be used as a reaction to block an attack, and provides an AC bonus. This makes Shield hard for any caster to bypass when choosing spells at first level.
Shield blocks Magic Missile automatically. You may cast Shield as a reaction to being targeted by Magic Missile. Casting the spell in this manner stops all of the darts that are targeting you.
You may cast Shield as a reaction to being hit with an attack. This instantly increases your armor class by 5. If this is enough to make the attack miss, then it misses.
If you cast Shield in either of these circumstances, the key thing to remember is that the +5 armor class bonus stays with you until the start of your next turn, in addition to protecting you for the same duration from Magic Missile.
The extended armor class bonus is almost good enough to make this spell a lock. The ability to cast it only when needed is what makes the spell as great as it is.
How Does the Shield Spell Work?
The Shield spell is cast as a reaction only when hit by an attack or when targeted with Magic Missile. This means Shield is different from the majority of other spells. It does not follow the rule of casting a cantrip or leveled spell since it doesn’t happen on your turn. For instance, if you cast a bonus action spell and then a cantrip on your turn and then are attacked on the enemy’s turn, you can still cast Shield.
Ultimately the spell description is vague as far as how the Shield actually manifests, providing only that a magical barrier of force surrounds and protects the caster. It has been determined that it takes the form of a large physical shield shape of energy. It does not produce a “bubble” of protection.
This determination has been made based on the bonus to armor class and that it does not provide immunity to damage or extra hit points. It functions as ¾ cover in the form of an energy wall. Likewise, it provides no protection to area of effect or resistance to single magic effects if paired with the Shield Master feat.
The barrier created cannot be used for any type of physical attack or action. For instance, it cannot be used for a shield bash attack or combination with shove.
Shield 5e and Other Reaction Spell Choices
Above it is outlined how Shield works as a reaction and how that differs from standard spells. Shield is not alone in its uniqueness, however. Below are several other choices for reaction spells, along with a short description.
- Absorb Elements – Allows the caster to capture elemental energy and deal it out on their next melee attack.
- Feather Fall – Allows the caster to slow the descent of up to five creatures within range to safe speed.
- Hellish Rebuke – Allows the caster to surround an attacker in hellish flames dealing damage after an attack.
- Counterspell – Allows the caster to interrupt the casting of another spell rendering it useless.
- Soul Cage – Allows the caster to capture a soul and manipulate it to your advantage.
War Caster Feat 5e
One of the biggest benefits of Shield is the ability to use it as a reaction. While unrelated, it is important to point out that the War Caster feat allows a spell to be cast as a reaction for an attack of opportunity. The spell must have a casting time of one action and only target that one creature. This allows the caster to cast multiple spells in the same round.
While Shield is a defensive only spell that benefits the caster on the battlefield exclusively, it remains a top choice for any caster. Casters, by nature, are most commonly the squishiest of the classes, so any opportunity to avoid damage should be held with high regard.
Casting the spell as a reaction doesn’t limit the casters ability to provide offensive firepower, so it avoids the conflict of other classes that use an action to cast buff or healing spells.