Our party was forced to brawl against a group of orcs in order to gain their respect to speak with their chieftain (long story, we had very good reason for doing this). It then became a battle royale.
Our wizard was at low health and next to our paladin, and had the idea to cast fog cloud to capture himself and the paladin within it so he could leave combat. He cast the spell, and then came down to the debate of whether the paladin would get an opportunity attack even though she was blinded.
The wizard was in threat range, but does an effect that causes an area to become heavily obscured cause the Paladin to lose threat range and the wizard be able to successfully flee to another area of the ring?
Or does the paladin still have threat range and attack the wizard, even with fog cloud covering both of them?
I looked over the rules for 15 minutes after this situation, but nothing came up. It was ruled in-game that it was fine to make an opportunity attack with disadvantage, but that just doesn't feel right. She might have heard the wizard stepping away, but the fog cloud was already in place. By the D&D rules, would the paladin have been able to make the opportunity attack or not?