The Wanderer is truly one who is shrouded in mystery because he resists attempts to pin him down into anything straightforward. Much like the mariner in
The Thorn, it is unclear exactly how he belongs in the story. Both seem to be transients, travelers who are not native to the soil of their tales but rather drift in and out, not really involved in the main plot. Yet, both also managed to inextricably thrust themselves into the scene before them. The mariner, stumbling along in the fog, practically runs headlong into Martha Ray and sees her face - probably no one had ever even dared to approach her before. The Wanderer actually shares in Margaret's confidence and has power both to touch and be touched by the story. At the same time, however, there hovers about him a strange ghost-like aura as though he flitted between worlds and only half belonged to any of them.
Exactly what relation the Wanderer had with Margaret or the Narrator is never made clear, yet it is undeniable that he was known to both. He calls them both "friend" and they likewise him, yet there never seems to be any attachment of permanence. He would be gone for entire lengths of time, yet whenever he returned for his brief visits with Margaret, it would seem as though the gaps in their relationship weren't there - they'd just pick up where they left off on terms of intimacy - then amidst her troubles, he would leave again just as he came, with nary a warning or explanation. With the narrator, it seems the exact same way. They just randomly run into each other on the road with impassioned greetings on both sides, yet they part for the night only to meet again the next day by appointment. The Wanderer wanders here and there touching his world lightly, yet seems to have bonds of uncommon force with those that he touches while simultaneously seeming to have no bonds at all.
In the way he tells Margaret's story is a hint of that deep yet always flitting, never definite quality. When the Wanderer speaks, his words so captivates his hearer and so draws him into the life being described
that "in my(narrator's) own despite, I thought of that poor Woman as of one Whom I had known and loved" and that "the things of which he spake seemed present". But the Wanderer refuses to stay within his story and constantly interrupts himself with apologies and interjections, constantly pushing himself back away from the story, and whenever he would distance himself, "there was in his face/ such easy cheerfulness, a look so mild,/ That for a little time it stole away/ All recollection; and that simple tale Passed from my mind like a forgotten sound."
The Wanderer's constant wandering and refusal to settle into a definite state, combined with his unexplained powers of attachment to both the narrator and Margaret, makes him a strange and almost terrifying character within the story.