How exactly does this interact/How would you have this interact?

[Morjoko]

Hello everybody, just had a question on how you would rule the interactions in the Psionic Weapon Discipline that the Mystic uses in Unearthed Arcana. Now when my player uses Ethereal Weapon and the creature makes the DEX saving throw, the ability says "On a successful save, the target takes half damage from the attack, but suffers no additional effects that would normally be imposed on a hit." Can he still use Lethal Strike to increase his damage?

Or I guess what I'm essentially asking is would you say the Lethal Strike is considered "an additional effect" for a melee hit or something else entirely?And if it isn't considered an additional effect what would be considered additional effects to melee hits then?

[Demonslayer666]

I would rule that Lethal Strike is an additional effect, and that it would not be allowed to be done on a successful save - it would only do normal weapon damage. Lethal Strike definitely 'says on a hit', and Ethereal Weapon says nothing additional on a hit.

[Finlam]

I would rule that Lethal Strike is an additional effect, and that it would not be allowed to be done on a successful save - it would only do normal weapon damage. Lethal Strike definitely 'says on a hit', and Ethereal Weapon says nothing additional on a hit.

I think this about sums it up.

I've also been curious how people would handle ethereal weapon with Great Weapon Master. A lot of people seemed against the idea of using them together, as it gives +10 damage without the -5 to hit penalty.

I'm not 100% convinced it breaks anything considering how limited the Mystic in damage capability right now; from level 5 onward (when second attacks come online for other classes) it would be a decent way of allowing their damage to keep up, something the class sorely needs at the moment. Not to mention it consumes 1 PP and a bonus action, effectively disallowing multiple attacks in a single round, unless you multiclass.

Now if you mutliclass it on the other hand, you've got a huge problem because you're the kind of person that allows players to multiclass the Arcane Mystic. It's clearly not ready for that yet as it would become an almost mandatory one level dip for most builds.

TLDR: Demonslayer666 has the right of it, but just bear in mind that from level 5+ the mystic has to go to lengths to keep up their sustained combat contribution, so be open to allowing +damage on ethereal weapon.

[Morjoko]

Thanks A lot!

My player was just trying out the class because he loves Psionics and was new to 5e. I looked at it and it didnt seem bad, at least comparable to other Unearthed Arcana stuff. But thats interesting, does it really fall off with reaching 5+? I mean with the many abilities targeting Int Saving Throws, I would think it would be a little better. But Im still relatively new to 5e at least with DMing.