This has to be the Porter, in Act 2 scene3, "Here's a knocking indeed! If a man where porter of hell-gate he should have old turning the key!"
The Porter behaves a little like Chorus, in other Shakespeare plays
being an interested spectator, but here, he is only in this very short scene, and reflects on the Gunpowder Plot of 1605, where Father Henry Garnett, "equivocated", under examination, not quite remembering who he was speaking to at the time, forgetting where they said they were going etc, etc.
As 'they' were the plotters, and as he was their confessor, the authorities took the view that Garnett knew exactly what was happening, and when, and where, so, he too, was hanged, drawn and quartered!
The Porter refers to three, seemingly different people, in the scene, however, they are all the same man, Garnett.
The Porter is awakened by MacDuff, and leaves the play when Macbeth is summoned.
Again, like Hamlet's Ghost, this is a small, yet powerful, part.
William Shakespeare often uses comic relief in all of his plays so that the audience can enjoy his plays a bit more than they usually do.