Shadow of Moil, from Xanathar’s Guide to Everything, is an interesting spell that is confusingly worded. A lot of the context needed to understand how the spell works is not in the text. It’s in understanding how the rules around vision and obscurement work. Here’s the text of the spell as a starting point:
Flame-like shadows wreathe your body until the spell ends, causing you to become heavily obscured to others. The shadows turn dim light within 10 feet of you into darkness, and bright light in the same area to dim light.
Until the spell ends, you have resistance to radiant damage. In addition, whenever a creature within 10 feet of you hits you with an attack, the shadows lash out at that creature, dealing it 2d8 necrotic damage.Shadows of Moil, Xanathar’s Guide to Everything, p. 164
I think it’s easiest to understand the effects of Shadow of Moil by looking at the type of senses the observer has. What I have to say here is consistent with the guidance Jeremy Crawford has provided on this spell:
Shadow of Moil by Vision Type:
- Vision – A “normally” sighted character cannot see through any darkness created by this spell. The caster is fully obscured. If darkness is created, the viewer with regular vision cannot determine the caster’s exact location within a 10-foot radius.
- Darkvision and Devil’s Sight– The spell does not specify that this darkness is magical. If the effect is within the range of the viewer’s dark vision, they can see through the darkness. However, the target is still fully obscured, and is not visible. Attacks against the target are at disadvantage and spells and effects that require the target to be seen cannot target the caster.
- Blindsight – A creature with blindsight can see the caster as long as the caster is within range of their blindsight.
- Tremorsense – A creature with tremorsense can see the caster of Shadows of Moil as long as the caster is within range and in contact with the same surface as the observer.
- Truesight – The observer with truesight can see through the darkness if it is within range of their truesight. The full obscurement still prevents them from seeing the caster. Attacks against the target are at disadvantage and spells and effects that require the target to be seen cannot target the caster.
That’s all for now! Here are some great monsters to throw at players using Shadow of Moil.