No concetration.   Nice use of a quickened bonus action for a multiclassing Sorcerer/Bard with Magical Secrets....

This spell gets even better when you realize that the 2d8 damage doesn’t have a set amount of activations apart from the amount of times you get successfully hit within 5 ft. So a horde of enemies ganging up on you or a creature with multiple attacks is in for a nasty surprise if they do not have damage reduction against cold/fire.

To clarify, there is no reason at all you can't use a combination of these spells for 2d8 Fire + 2d8 Cold damage and resistance to both?

Quote from SergeTroy >>

To clarify, there is no reason at all you can't use a combination of these spells for 2d8 Fire + 2d8 Cold damage and resistance to both?

 There is. Namely Basic Rules: Chapter 10: Spellcasting / Combining Magical Effects. To quote:

The effects of different spells add together while the durations of those spells overlap. The effects of the same spell cast multiple times don't combine, however. Instead, the most potent effect--such as the highest bonus--from those castings applies while their durations overlap, or the most recent effect applies if the castings are equally potent and their durations overlap.

For example, if two clerics cast bless on the same target, that character gains the spell's benefit only once; he or she doesn't get to roll two bonus dice.

If you cast Fire Shield on yourself twice, you only get the effects of the shield you cast last.

Looks like a good opportunity for a fire shield, armor of agathys combo

Fun fact.  I actually managed to kill a Lich using this.  The Lich tried to use paralyzing touch.  Needless to say, it didn't work out well.  The conversation went something like this:

DM:  "The Lich is going to use paralyzing touch.  It hits."

Me:  "Cool.  Before I roll my save, he takes 2d8 fire damage."

DM:  "...the Lich dies.  How long have you had that up?"

Me:  "I put in on at the start of the fight.  I even announced  I was doing it in cinematic fashion."

DM:  "Well, crap.  Well played."

pact of the blade warlock+this spell+pole arm master feat

if you make your pact weapon a weapon that benefits from this feat (spear, glaive, halberd, quarterstaff, etc), nothing can come into melee range of you, because of opportunity attacks and if you miss and they manage to hit you, they take a lot of fire/cold damage. unfortunately you can't be a hexblade warlock, but you can also do this with a battle smith, you just need a pole arm, high int score and the enhanced weapon infusion

Don't forget, you can cast this and then deliberately provoke opportunity attacks to try and deal the damage on your turn. Depending on initiative order, you could free up your allies to move around with this tactic. This also applies to Armor of Agathys if you're a Warlock.

I know the damages stack when this is cast in combination with Shadow of Moil by a Fiend Warlock, but how does the light producing aspect of this spell combine with the light eliminating aspect of Shadow of Moil?

This spell description has the only typo I've found so far in the errata'd PHB. I was surprised to see that the error also exists here online! The last sentence should read,

The attacker takes 2d8 fire damage from a warm shield, or 2d8 cold damage from a cold chill shield.

Quote from gabrielrockman >>

I know the damages stack when this is cast in combination with Shadow of Moil by a Fiend Warlock, but how does the light producing aspect of this spell combine with the light eliminating aspect of Shadow of Moil?

 

 

Beyond 20

 

 

 

 

 

 I'd think of it as one single fire that creates light and destroys it at the same time, exploding in a cosmic explosion of energy. My reason for a cosmic approach is the damage types, with the necrotic damage being like the darkness of either the far realm or space, the fire damage reminding me of a dying star (when paired with the necrotic), and the cold damage resembling the cold of a comet or a bit of a dazzling nyxborn effect. Although with a fiend warlock there'd probably be a different look, like maybe one of the layers of the nine hells, and you're channeling energy from that layer to not only produce death, but also partially bringing that layer to the material plane or wherever you are.

With Tasha's expanded spell list for druids.. i intend to turn into a giant constrictor snake with this on to tank and have a field day

Also.. this plus Sentinel means "either im hitting you. Or you're getting burned when you hit me" to any adjacent melee opponents

 In the "Available For" section it should have some sort of tag for being added to Druid list with the options from Tasha's.

I want to ask. This spell was not avalidable for the sorcerers in Tasha?

Perfect for a high level Eldritch Knight.

Fire Shield + Polymorph :D

Fire shield is also neat if you put it on a ring of spell storing and give it to the front line fighter

If a sorcerer were to use Transmuted Spell on this, would they then get resistance to the new damage type (transmute it to Lightning, thunder, acid etc)?

I cant find Fire shield in my known spells on the app for android. Is there a mistake

While the Lich would die from the fire damage the fact that they took the damage means their attack hit so you should have still taken the Paralyzing Touch.

Quote from bluxmoore >>

I cant find Fire shield in my known spells on the app for android. Is there a mistake

 

 

Beyond 20

 

 

 

 

 

 It was only added to the Druid spell list in Tasha's, so you either need that book or add it manually as an extra spell.