Looking for advice on this, as it would be the first time I use the Banshee.  Could a party of four, level 3 characters (Barbarian, Cleric, Wizard, Warlock) feasibly take this on barring bad rolls yadda yadda, as the climax of a story arc?  What are some DM's experiences with using these on lower levels?

The wail has a potential for a TPW, but I like the thought of putting these characters on the edge of their seat.  I might develop a safety net if its felt that four level 3's shouldn't be taking this on.

Any feedback would be great!

DM: Trentos

Four lvl 3s would tear this thing apart. She could probably take out one or two of them (which the cleric would heal), but then the party still has two or three actions and presumably two or three bonus actions before her next turn. Assuming the three non healers did about ten damage each per turn, she'd be dead in two rounds.

Using two of them would probably tpw, but I would say jack up her hit points, add environmental dangers, or add other, weaker undead.

You could also change her tactics so that she only wails if she's in serious danger, or tries to split them up. Keep in mind she only wails once and at least the barbarian will likely succeed

Great feedback, thanks!

@Trentos_Shadewalker

I know I'm a little late to this but, you could also add new features and abilities to make it a more challenging fight, such as adding abilities like

Phantasmal Grasp
Concentrated Physical Ability, much like a grapple but if the Dex Save fails is guaranteed to happen as the Banshee phases through your attempts to counter until her arms and legs wrap around your body, holding on to you. You are free to move but any attempt to remove her causes 1d10 necrotic damage as she tightens her hold and while any outward weapon will have a chance of hitting her, it is also likely to hit you as well.

Would give her very strong melee-ability against a level 5+ group especially if it was a Haunt (I think is the correct turn for something like this) of Banshees (ie a group vs group rather than group vs 1) or if you wanted her to be more ranged focused.

Corrupting Aura
Passive Trait, death and corrosion follow this being wherever they go, killing plants, sickening animals, and leaving a swath of eeriness and unease in their wake. Con Save success deals 1d4+1, Con Save fail deals 1d6+2. (does not affect undead or constructs)

Or just a block ability where she focuses on her etherealness and phases out of reality (essentially loses her physical form and cuts her movement speed in half or down to one quarter)

A slow transformation of a twisted person into a truly tortured soul. Imagine how many people they would have torn down with them as they realized the nature of their demise. 

In her final moments she remembered. A faint memory of her mother telling her stories when she was a girl​. "... and the beautiful woman wailed for she realized what she had become. Little one this is the true price of vanity and manipulation. Ones who take from others, shall to be taken."

Unless you've loaded down your level 3s with magic weapons, this would be a deadly encounter for them. They deal half damage with non-magic weapons, fire, lightning, acid, thunder, and it's immune to cold, poison, and necrotic damage.

That leaves magic weapons, psychic, and force damage as the only unresisted types.

Meanwhile, she has a DC13 con save or automatically unconscious (death saving throws)

This is missing its environment tags: Coastal and Forest.

It so great

this thing is scary! it would destroy 2 lv2 dwarf paladins and a high elf lv2 wizard

That wail is nasty, but suitably so.

As a lvl 3 Human Paladin who just killed one of these, I almost 1 hit KOed a Banshee with a crit that was smite. 2d8+5 weapon damage and 6d8 Radient damage. Along with the Elderitch Blast the warlock did before I hit, she was down before she could have a turn. 

im sorry your math

at level 3 do you have a magic weapon? if not [2(1d8)+5]/2

and a 6d8 smite I assume is 3d8 then crit for 6? is a level 2 spell slot but a level 3 pally doesn't have a level 2 slot so 2(2d8).

so a crit from a level 3 paladin w/o a magic weapon. Min 7 Max 26 Avg 14  with a magic weapon Min 9 Max 53 Avg 32

Hp of a banshee is Min 13 Max 104 Avg 58

so w/o a magic weapon it should take about 4 crits with a magic weapon it should take about 2 crits

So your Dm

1 let you hit a lot harder then you can

2 gave you a ****** banshee

tldr Your DM is very nice

Not to be that guy but Divine Smite deals an extra 1d8 against undead so no it actually is a 1st level smite dude. I would also point out that he said he nearly one shotted it. We don't know how hard the next person hit so you really don't need to try and undermine the guys moment. So anyway, rounding down as you do:

Min 9, Avg 34, Max 58, without a magic weapon. 

Min 13, Avg 41, Max 69, with a magic weapon.

Hp of a Banshee is as you say Min 13, Avg 58, Max 104.

So his DM:

1 Didn't let him hit a lot harder then he could, he actually knew the correct rules for Divine Smite.

2 May or may not have given him an average banshee, we have no idea because we have no idea if the DM rolled for HP for the banshee, had them start with magical items or any one of many other factors.

But even if he didn't roll for HP and just used the average it is still theoretically possible to do the damage to kill it with a non magic weapon if he rolled perfectly. I don't think there is any need to imply his DM is pulling punches given the situation as we can see it. The guy has a cool memory from a cool moment when he nearly got to one shot a nasty creature and there is no need to try and tear that down. 

Sorry dude, like Shadreq said, a smite against an undead is 3d8. Check your facts before trying to fact check someone.

For the record, checking my Roll20 account, I did 14 damage with just the weapon, lowered to 7 due to resistance, and I rolled 38 with the radiant damage, dealing a total of 45 damage.

Adding in the previously mentioned Elderitch Blast which dealt d10+4 (Agonizing Blast) for 13 damage, I managed to take down the Banshee with 1 strike.

The DM uses the average HP for creatures. From what I've encountered, that seems pretty common place.

In total, we did 58 damage, the exact HP of creature. It was the Banshee's turn next. Nothing bad happened. It was AWESOME! But thanks for trying to ruin it with a bad rational and assuming we did it wrong and that it wasn't an amazing moment of luck.

@Shadreq thanks for the backup 

Wow. Just wow. This is nearly as good an excerpt as the Encyclopedia Britannica 

It took out 3 of 5th level charakters in my campaign with wail. They ware suprised

its a ghost!!!!

What are its weaknesses?

Quote from BillyBuster >>

What are its weaknesses?

 Mirrors, they hate those.  They’re vane, and don’t like being reminded of how monstrous they’ve become.

A generous DM might even let you reflect it’s Horrifying Gaze back at it.  Silver-backed are especially good for flavor.

Quote from Trentos_Shadewalker >>

Looking for advice on this, as it would be the first time I use the Banshee.  Could a party of four, level 3 characters (Barbarian, Cleric, Wizard, Warlock) feasibly take this on barring bad rolls yadda yadda, as the climax of a story arc?  What are some DM's experiences with using these on lower levels?

The wail has a potential for a TPW, but I like the thought of putting these characters on the edge of their seat.  I might develop a safety net if its felt that four level 3's shouldn't be taking this on.

Any feedback would be great!

DM: Trentos

 

 No, because the banshee cannot take two characters of level four (cleric, wizard)