D&D 5E Help on Chaos Hammer spell conversion?

[Quickleaf]

I'm looking to convert an old spell called Chaos Hammer, which you may know from its 3rd edition version (ranged area effect that dealt force damage - no damage if you were chaotic, and 1/2 damage if you were neutral/unaligned - and slowed the targets), but originated in the 2nd edition Hellbound boxed set (bursting sphere around the caster that dealt force damage and knocked targets prone - no effect if you were chaotically aligned).

I'd like to incorporate the spirit of both past versions into a 5th edition spell I can give some demons in my game, and which can be discovered and used by the PCs if so inclined. However, a straight conversion of the 2e version feels a lot like thunderwave, while a straight conversion of the 3e version is a weird force fireball combined with a slow spell...

So I want to design this to occupy its own cool niche in the 5e spells.

CHAOS HAMMER (2nd edition)
(Invocation/Evocation)
Level: 4
Range: 0
Duration: Instantaneous
Area of Effect: 100-foot globe
Components: V, S, M
Casting Time: 4
Saving Throw: Va

The chaos hammer spell was developed by a marilith named Theiras — a tanar'ri not known for her subtlety. Fact is, the baatezu have yet to develop a counterpart to this devastating offensive magic.

When cast, chaos hammer projects waves of concussive force in all directions from the wizard. The waves harm any sod in the area of effect who is of a lawful or neutral alignment. Victims suffer 5d8 points of damage (save for half) and must make a successful Strength check or be thrown to the ground.

Folks of chaotic alignment are immune to chaos hammer.

The tanar'ri know that the spell won't bother them or their allies, so they cast it freely in the middle of a melee. The material component for this spell is a bit of flesh from a lawful creature.

Here's my first attempt at converting the spell. Does this succeed or fail as a spell? Would you (or have you) converted Chaos Hammer differently? Is anything about the writeup unclear? Is it appropriate for a 4th level spell?

Chaos Hammer (rough draft)
4th level evocation (cleric, sorcerer, warlock, wizard)
Casting Time: Action
Range: Self
Components: V, S
Duration: Concentration, up to 1 minute

Waves of multicolored concussive annihilating force emanate outward from you. Each creature in a 20 foot cube originating from you must make a Wisdom saving throw. On a failed save, a creature takes 3d8 force damage. On a successful save, the creature takes half as much damage.

A creature of chaotic alignment has advantage on its saving throw.

For the spell’s duration waves of force continue to emanate from you in a 20 foot cube. If a creature that failed its saving throw attempts to move closer to you, it treats the area as difficult terrain and suffers 1d8 force damage per 5 feet moved towards you.

 

[Quickleaf]

Made a few edits so far...

Chaos Hammer (v 0.1)
4th level evocation (cleric, sorcerer, warlock, wizard)
Casting Time: Action
Range: Self
Components: V, S
Duration: Concentration, up to 1 minute

Waves of multicolored concussive annihilating force emanate outward from you. Each creature in a 20-foot radius sphere originating from you must make a Wisdom saving throw. On a failed save, a creature takes 3d8 force damage. On a successful save, the creature takes half as much damage.

Demons, slaadi, and other creatures of pure chaos are immune to this spell.

For the spell’s duration waves of force continue to emanate from you in a 20-foot-radius sphere, which move with you and is centered on you. If a creature enters this area for the first time on its turn or starts its turn there, it must succeed a Wisdom saving throw or it treats its movement towards you in the spell’s area as difficult terrain, suffering 1d8 force damage per 5 feet moved towards you.

 

[Stalker0]

So this spell actually looks very similar to Spirit Guardians.

SG is a 15 foot radius but has no effect on allies and lasts 10 minutes per level. The difficult terrain is automatic, requiring no save. Meanwhile the damage does require a Wisdom save.

So I feel like this spell does not compare well to SG which is a level lower.


I personally would go with one of two ideas:

1) Use a prone effect that is similar to the 2e version. Make a strength save or become prone.
2) Add back in the slow effect from 3e against lawful creatures.

 

[Quickleaf]

Thanks @Stalker0 ! I hadn't thought to compare it to spirit guardians. Great idea.

I definitely want to integrate the past versions, rather than just do a straight conversion of either 2e or 3e's Chaos Hammer.

The 2e version is basically a bigger badder thunderwave but swapping out "pushed 10 feet away" for "knocked prone", while the 3e version is sort of like a shatter / fireball, and slow spell combined. Those versions of Chaos Hammer seem a bit too close to design space already occupied by existing spells.

It's possible the needle I'm trying to thread is too narrow, but I think there's a design space for this spell between fire shield, spirit guardians, thunderwave, shatter, and slow.

Let me take another stab and explain my thought process...

• There's an initial effect, which I imagine as the outermost in a series of ripples / bullseye circles. This chaotic "front" deals more initial damage (4d8) and can knock creatures off their feet. It doesn't differentiate friends from foe.
• The ongoing "smaller" waves of force create conditional difficult terrain – anyone moving towards caster acts as if in difficult terrain.
• Creatures starting or entering this area full of these waves of force must make a save or take damage (1d8 per square moved towards you).
• Riffing off of chaos bolt, and the mention of "leaping, ricocheting energy" from the 3rd edition version, if a creatures takes multiple d8's of damage while approaching you, and the same number is rolled on two of those d8's, then there is a ricochet effect for another creature in the spell area. This makes it nasty towards hordes trying to close into melee with you.
• Certain creature types are immune ("Demons, slaadi, and other creatures of pure chaos are immune to this spell"). 5e's spells have examples of creature type being excluded (typically undead/constructs), but no examples dictating targets according to alignment.

Chaos Hammer (v0.3)
4th level evocation (cleric, sorcerer, warlock, wizard)
Casting Time: Action
Range: Self
Components: V, S
Duration: Concentration, up to 1 minute

Waves of multicolored concussive ricocheting force emanate from you to a distance of 20 feet for the duration. Creatures treat all movement towards you in the area as difficult terrain.

Each creature in a 20-foot radius sphere originating from you must make a Strength saving throw. On a failed save, a creature takes 4d8 force damage and is knocked prone. On a successful save, the creature takes half as much damage.

When a creature enters the area for the first time on a turn or starts its turn there, it must succeed a Strength saving throw or take 1d8 force damage per 5 feet moved towards you within the area. It takes this damage when it stops moving towards you.

If you roll the same number on two of the d8s of damage dealt to one target, the chaotic energy leaps from the target to another creature of your choice within 20 feet of you. The new target cannot have already succeeded a saving throw against this spell this turn. The new target must roll a Strength saving throw as above, and if it fails you make a new damage roll, which could cause the chaotic energy to leap again.

Demons, slaadi, and other creatures of pure chaos are immune to this spell.