Does blocking an attack with the Shield spell still trigger Armor of Agathys?

I am contemplating a Oath of Conquest Paladin / Sorcerer multiclass character, with a 1 level dip in hexblade warlock.

This character will have access to the Armor of Agathys and Shield spells, which potentially allows for a pretty nice combo.

The Shield spell states (PHB 275):

Casting Time: 1 reaction, which you take when you are hit by an attack or targeted by the magic missile spell…

Until the start of your next turn, you have a +5 bonus to AC, including against the triggering attack,

It looks like you are indeed hit by an attack, but since you have a bonus to AC, you can potentially force that attack to miss instead.

Armor of Agathys states (PHB 215),

If a creature hits you with a melee attack while you have these hit points, the creature takes 5 cold damage.

If I cast Shield and cause an attack that "hit" me to miss, does Armor of Agathys still deal damage?

I am leaning toward yes, though this combo seems a little too strong–Shield is already a strong spell, and this character will eventually have 9 1st level spell slots and a 7th level spell slot. Not only can they freely block attacks with Shield, but they can also deal up to 35 (5d10) damage to the attacker without an attack roll or saving throw. While a Warlock would have to spend both of their spell slots to do this once, my character would be able to do this 4 times with spell slots to spare.

Some notes:

  • Related questions ask about reducing the damage from a confirmed hit to zero. This question is asking about what happens when the Shield spell causes the attack to miss entirely.
  • A number of online resources, such as the Roll20 5th edition compendium, seem to be missing the correct casting time for the Shield spell. Answerers should make sure they’re looking at the correct version from the PHB.

Shield spell – removing the special effects of a hit


Background

A Shield spell is cast as a reaction to an attack that hits. It applies its AC bonus even against the attack to which it is a reaction, meaning that it can make the attack that hit, retroactively miss and thereby not do damage.

Shield ‘interrupts’/potentially cancels its trigger, as stated in the DMG in the ‘Adjudicating Reaction Timing’ section.

Since the hit has retroactively become a miss, what happens to effects that were triggered by the hit in the first place? Are they undone as well, or do they persist?

This question has two answers of nearly equal popularity, with one arguing that other effects triggered by the hit still persist, and the other arguing that they do not. On the side of the argument that they do not occur is a (now-unofficial) tweet from Jeremy Crawford stating

If the attack has a special effect that relies on it hitting, that effect doesn’t occur if the attack is turned into a miss.

However, the discussion therein focusses on a narrow interpretation of ‘effects’ as discrete, measurable things that happen to specified targets – the hit on the caster of the Armor, and the resulting damage to the creature making the attack.

Are the ‘special effects’ of an attack referred to limited to things like damage or conditions that affect just the target of the attack, or do they include intangibles like knowledge for all intelligent observers?

Scenario

A party is traversing wilderness with abundant natural cover as well as opponents who are seeking to ambush them.

A hidden opponent fires a missile weapon at a party spellcaster and hits. In response, the spellcaster uses the shield spell and turns the attack into a miss. However, the ambusher has now revealed their location to the spellcaster and everyone else in the party, since according to the rules of Unseen Attackers and Targets

If you are hidden–both unseen and unheard–when you make an attack, you give away your location when the attack hits or misses.

The party members begin to defend themselves and target the ambusher.

The next round, a second hidden ambusher also fires at the spellcaster, hits, and also reveals their presence to the caster and the rest of the party. The spellcaster again uses shield, and again converts the hit into a miss.

This second ambusher, however, possesses the Skulker Feat (PHB 170)

When you are hidden from a creature and miss it with a ranged weapon attack, making the attack doesn’t reveal your position.

Since the attack was now actually a miss, does the knowledge of ambusher’s location persist as revealed, or is this knowledge undone?

Does…
…the shield spell travel back in time, converting the hit to a miss before the party had knowledge of the second ambusher’s location?

…knowledge of the ambusher’s location count as a ‘special effect’ of the attack hitting, that now does not occur since the attack resolved as a miss?

…the ‘special effect’ of the knowledge of the ambusher’s location get removed from only the caster, while their companions still know where the ambusher is?

…the knowledge of the ambusher’s location not count as a ‘special effect’ of the attack, but rather as mundane effect, that is not changed by the shield spell?

A good answer may use the Crawford quote or not. If it does, it should convincingly interpret what is a ‘special effect’ and to whom it applies. If the answer does not use the Crawford tweet, it should explain from where it draws its reasoning.

As a sword and board Eldritch Knight do I need to put away my sword on my turn if I want to use Shield as a reaction?

Without Warcaster, I can’t cast spells with somatic components if I have both a shield and a sword in my hands. Putting my sword away or dropping it is a free action, however you can’t do free actions outside your turn. So if I want to be able to cast Shield on myself as a reaction, do I need to always put my sword away at the end of my turn? (This also means I won’t be able to capitalize on opportunity of attacks).

Shield Spell and triggering effects of damage not taken

A Shield spell is cast as a reaction to an attack that hits. It applies its AC bonus even against the attack to which it is a reaction, meaning that it can make that attack that hit, retroactively miss and thereby not do damage.

Shield ‘interrupts’/potentially cancels its trigger, as stated in the DMG in the ‘Adjudicating Reaction Timing’ section.

Since the damage has retroactively not been done, what happens to effects that were triggered by the damage in the first place? Are they undone as well, or do they persist?

This question has two answers of nearly equal popularity, with one arguing that other effects triggered by the hit still persist, and the other arguing that they do not. On the side of the argument that they do not occur is a (now-unofficial) tweet from Jeremy Crawford stating

If the attack has a special effect that relies on it hitting, that effect doesn’t occur if the attack is turned into a miss.

If we accept that Shield means the effects of a hit retroactively do not happen, what occurs when those effects include ones that allowed the Shield spell to be cast in the first place?

I am currently running Curse of Strahd and in today’s session the party was fighting flameskulls, which are undead capable of casting the Shield spell.

  1. The party cleric had turned multiple flameskulls.
    "Channel Divinity: Turn Undead":

A turned creature must spend its turns trying to move as far away from you as it can, and it can’t willingly move to a space within 30 feet of you. It also can’t take Reactions.

At the start of the paladin’s turn, the flameskull could not cast Shield, since it was Turned, and could thus not use reactions.

  1. The party paladin then attacked a flameskull that had been turned, and hit, causing damage.
  2. This damage removed the turning effect on the flameskull, allowing it to cast spells.
    "Channel Divinity: Turn Undead"

it is turned for 1 minute or until it takes any damage.

Once the flameskull had taken damage, it was no longer Turned. Since it was no longer Turned, it was able to use its reaction, and thus able to cast Shield.

  1. As a reaction, the flameskull cast Shield, which resulted in the effect that it was retroactively not hit.

  2. Since it had not been hit, it had not taken damage. What happens next?

Option A: Although the damage as a consequence of the hit is removed, the fact that the damage was done at one point in time was enough. The spell slot for Shield is removed, the flameskull is undamaged but no longer turned, and it finishes its turn.

Option B: Since the damage as a consequence of the hit is removed, the flameskull is retroactively still turned. The spell slot for Shield is removed, but the flameskull is still Turned, and finishes its turn.

Option C: Since the damage as a consequence of the hit is removed, the flameskull is retroactively still turned. The spell slot for Shield is removed. Since the flameskull is retroactively still Turned, it could not have taken a reaction and thus did not cast the Shield spell. The spell slot for the Shield spell is restored. Since it did not cast Shield, the flameskull was actually hit and took damage. Since it was damaged, it is no longer turned and can now cast Shield. The flameskull never finishes its turn because it is caught in an infinite recursion loop.

Can a mundane shield be used with Mage Armor?

Mage armor:

You touch a willing creature who isn’t wearing armor, and a protective magical force surrounds it until the spell ends. The target’s base AC becomes 13 + its Dexterity modifier. The spell ends if the target dons armor or if you dismiss the spell as an action.

A shield grants a +2 bonus to AC, and is in the list of equipment that can be donned and doffed. Can the spell be cast on someone wielding a shield, and would it end if cast on a person who then dons a shield?

As a sidenote, while this question shares similarities with a previously asked question (Does Mage Armor stack with Shield?), that question deals primarily with whether untyped bonuses can add onto mage armor, and whether the two spell effects can combine, whereas this question queries a specific limitation of the mage armor spell (cannot work with armour) and whether a shield counts as armour in this regard.

If a creator of a Shield Guardian gives the control amulet to the Shield Guardian, what would happen?

There was an idea pitched at one of my play sessions earlier this week that has been gnawing at me. Suppose a wizard creates a shield guardian and gives the golem the telepathic command to take off the amulet and live a life of its own; what would happen?

Would the Shield Guardian become a sort of pseudo-warforged, following the original command? Would it just be stuck, standing there?

would Sacred Flame hurt a person the target is holding as hostage/human shield?

An enemy had grabbed a friendly NPC and was using him as a hostage and standing behind him as cover. The (new) DM seemed to be implying that the archers in our party would risk shooting the friendly. I thought sacred flame would be good because it can target creatures in cover and seems to go through environment without damaging anything else. So we reasoned sacrad flame would just fry the enemy and leave our friendly unharmed. Thoughts?

Can a Shield be Disarmed?

The Player’s Handbook describes the shield as being wielded in one hand.

However, the Armor category that displays the times to put on armor lists the shield is something that you don, and it takes one action to do so. Under this interpretation, can you even be disarmed of your shield, very much the way you cannot be disarmed of your armor?