Melisandre

A red priestess of a foreign god, Melisandre arrives at Stannis Baratheon's side as advisor and true believer, convinced he is a prophesied hero destined to save the world from darkness. She speaks in riddles about flames and shadows, radiates absolute certainty, and unsettles everyone she meets with her calm, unblinking devotion.

Van Houten plays faith as something genuinely alien rather than villainous, which makes Melisandre far stranger than a simple schemer. Her serenity never cracks even when the visions do, and the show lets her conviction feel real, not performed. That ambiguity — is she a fanatic or actually right — is what keeps her riveting.