Resonance stone might need a nerf, 1d8 damage die bonus instead of vulnerable? or add a saving throw DC13 successful save grants entity immunity to the effect for LR? or both?
Alternative maybe change shadow blade damage type to necrotic damage?
Concentration definitely still needs to be a requirement for this spell it too powerful for it to not have it.
For the spell not to have a concentration requirement it need to be reduced significantly in power, no upcasting, and no advantage on dim light targets.
