Melisandre is basically a walking question mark, with no real indication of her motives or end-game, with the only set-in-stone fact about her being that she's not shy when it comes to seduction and manipulation. She's obsessed with noble blood, especially if it's flowing through a bastard son's veins, with Gendry being leeched in Season 3. Speaking of him, is he still just endlessly rowing his boat around the world or will he make a comeback? Jon Snow is her latest target and the line: "In our joining, theres power. Power to make life, power to make light, power to cast shadows, suggests she wants another shadow baby like the once she created with Stannis to wipe out Renly Baratheon. While her "you know nothing, Jon Snow" did provoke a feeling of 'not again...' it also adds intrigue as to how she even knew about Ygritte's trademark line.