if a creature is heavily obscured and your in melee with it, what is the ruling? Does it have a plus 5 bonus to ac, do you have disadvantage against it, or something else?Cover is meant to represent a physical barrier that improves your armor – IMO, anything to do with lightning conditions should impose disadvantage as appropriate

— Mike Mearls (@mikemearls) January 29, 2018

So in this case, in XGTE, the spell Shadow of Moil causes the caster to become heavily obscured. Is the intention just to make it harder to hit the caster with a repercussion of taking damage? What bonus does h. obscurity provide the caster? Thanks and sorry for all the questions No worries! Heavily obscured normally grants disadvantage on attacks. A creature might be able to ignore the effect if it has no impact on its senses. Smoke would not affect a creature with tremorsense

— Mike Mearls (@mikemearls) January 30, 2018