Appears in Act 1, Scene 2 of the play where he claims to wear no mask. His face (or identity) seems to be in fact the Pallid Mask. He most likely either acts as an emissary for, is an avatar of, or is the dread entity known as the King in Yellow.
He/it is one of only three characters known for certain to be in the play, according to the scant detail available in the actual writings of Robert W. Chambers – the other two named being Camilla and Cassilda.
In the play script given in More Light, the Stranger is stated to be from Aldebaran and – contrary to other interpretations – an enemy of The King In Yellow. It is implied he is identical to The Phantom of Truth as Truth is stated by him to have been invented as a weapon for use against the King.