Can a spellcaster anticipate that the duration of a spell he’s concentrating on is about to end?

For example, when a wizard casts invisibility, that target is invisible until they attack or after the duration of an one hour. Say a player wants to explore for 59 minutes, then duck into an alley as the duration expires. It would be a challenge for anyone to anticipate, by the second or even by the minute, when a 60 minute interval is going to end. Or maybe they would feel the spell waning?

This is similar to Does a spellcaster know when concentration ends?, but it’s a different question.

Does dealing 0 damage to a concentrating spellcaster require a saving throw?

Wizard is currently concentrating on a spell. Wimpling has a -1 Strength modifier, and makes a melee attack on Wizard. The attack hits, but Wimpling rolls a 1 on the damage roll, meaning that after applying his Strength modifier, he deals 0 damage.

Per the SRD, Damage Rolls (and in more recent Player’s Handbook printings):

With a penalty, it is possible to deal 0 damage, but never negative damage.

From the Spellcasting chapter, Concentration:

The following factors can break concentration:

Taking damage. Whenever you take damage while you are concentrating on a spell, you must make a Constitution saving throw to maintain your concentration. The DC equals 10 or half the damage you take, whichever number is higher. If you take damage from multiple sources, such as an arrow and a dragon’s breath, you make a separate saving throw for each source of damage.

But I’m not sure if “dealing 0 damage” means that the target “takes damage”. Does Wizard need to make a Constitution saving throw to continue concentrating on the spell?

I’d prefer official sources or references if available. If there aren’t any, then I would accept any semi-official or well-informed well-reasoned arguments, preferably backed up by whatever evidence is available.

Can you use divine smite while you are concentrating on a spell as a warlock/paladin in DnD 5e?

So I am playing as a hex-blade warlock 3/paladin 2 in a dnd 5e campaign, and I’m wondering can you use your paladin divine smite ability in melee while you are concentrating on a spell such as shadow blade or hex?

Because, while Divine Smite does consume spell slots it is not a spell, therefore is it reasonable to suggest that you can use divine smite while concentrating?

How to obfuscate an enemy caster concentrating a spell in a group of enemy casters?

My players face a cult of wizards in a ruin. All cult members wear identical robes and conceal their faces with masks.

One of the PCs is a fighter and has shown to be particularly effective as dispatching other wizards in the field, so this group of wizards will try to disable him from combat via casting Heat Metal, then the rest of the wizards will protect this wizard until the fighter is disabled.

My question is twofold: mundane effects to obfuscate the caster and magical effects to obfuscate the caster.

  1. What mundane things could be done to hide the caster?

Since all the wizards are identical in appearance, I believe if they all perform the verbal and somatic components in unison the PC wouldn’t know which caster to focus.

  1. Are there any magical effects that could conceal the caster?

Invisibility cast by a second wizard on the primary after Heat Metal is cast could work. Minor Illusion could break line of sight to prevent ranged attacked.

Does casting Inflict Wounds while concentrating on Vampiric Touch also siphon damage?

Vampiric Touch says,

The touch of your shadow-wreathed hand can siphon force from others to heal your wounds. Make a melee spell attack against a creature within your reach. On a hit, the target takes 3d6 necrotic damage, and you regain hit points equal to half the amount of necrotic damage dealt. Until the spell ends, you can make the attack again on each of your turns as an action.

Scenario:

  • Round 1 you cast vampiric touch and make a melee spell attack for 3d6 necrotic damage.

  • Round 2 while still concentrating on vampiric touch you cast Inflict Wounds as a 3rd level spell for 5d10 necrotic damage.

Being that Vampiric Touch is still functioning, you are making a melee spell attack, and it is dealing necrotic damage… Does the necrotic damage from Inflict Wounds siphon health?

(Obviously the 3d6 and 5d10 wouldn’t stack because of action economy, etc.)

I am sure that a player could find a better use of two 3rd level spell slots, but I have taken up a kind of awkward place as an arcane healer/tank for the group and every bit of preservation helps.

Can you concentrate on a special ability while also concentrating on a spell?

There exist several abilities that have the text similar to, this effect lasts while you maintain concentration (as if you were concentrating on a spell). One such example is the Bard College of Glamour: Mantel of Majesty abililty.

At 6th level, you gain the ability to cloak yourself in a fey magic that makes others want to serve you. As a bonus action, you cast command, without expending a spell slot, and you take on an appearance of unearthly beauty for 1 minute or until your concentration ends (as if you were concentrating on a spell). During this time, you can cast command as a bonus action on each of your turns, without expending a spell slot.

Another example is the Cleric Trickery Domain: Channel Divinity: Invoke Duplicity ability.

Starting at 2nd level, you can use your Channel Divinity to create an illusory duplicate of yourself.

As an action, you create a perfect illusion of yourself that lasts for 1 minute, or until you lose your concentration (as if you were concentrating on a spell).

While you are concentrating on maintaining such an ability would you also be able to maintain concentration on a spell that requires concentration?

There does not seem to be any RAW that limits this however the limitation around concentrating on a second spell exists which may suggest that the intent is that a character cannot concentrate on 2 effects at the same time unless explicitly stated.

What kind of action is stopping concentrating on a spell?

Our party’s initiative order is like this:

  • 20 – Bard
  • 19 – Bad guy
  • 18 – Bad guy
  • 17 – Bad guy
  • 16 – Bad guy
  • 15 – Nobody
  • 14 – Ally
  • 13 – Ally
  • 12 – Ally

Can my bard cast calm emotions such that the bad guys cannot take violent actions on their turns, and then stop concentrating as a free action at initiative position 15 so that my allies can act fully?

Does Planar Binding require you to keep concentrating on the summoning spell?

Planar binding states:

With this spell, you attempt to bind a celestial, an elemental, a fey, or a fiend to your service. The creature must be within range for the entire casting of the spell. […] At the completion of the casting, the target must make a Charisma saving throw. On a failed save, it is bound to serve you for the duration. If the creature was summoned or created by another spell, that spell’s duration is extended to match the duration of this spell.

Most summoning spells require concentration. Would the original caster be required to continue concentrating on that spell even when planar binding extends the duration?

I was inclined to say “yes” to this, but it was pointed out that upcasting planar binding extends its duration to as much as a year and a day.

At Higher Levels. When you cast this spell using a spell slot of a higher level, the duration increases to 10 days with a 6th-level slot, to 30 days with a 7th- level slot, to 180 days with an 8th-level slot, and to a year and a day with a 9th-level spell slot.

It seems really unreasonable to expect concentration to be even over these extreme lengths of time.

Am I missing something here?

So, does planar binding require the original caster to maintain concentration on the extended summoning spell when one is present?