The Asmodean part is especially obvious. It's hinted at very strongly throughout the book, and I assumed that part at the end was Brandon's not-so-subtle and final confirmation that it was indeed Graendal. The case has, I believe, put to rest.

Many people also think that the final scene with Lanfear in chains is an illusion. Lanfear knows Rand, and she's playing on his one weakness--his inability to harm a woman, no matter how dangerous she is. While it's possible that Lanfear has "come to the Light," we know Lanfear as well--she's evil, unbelievably jealous, and she joined the Shadow because of her jealousy towards Rand. He's flat out rejected her, and she has finally accepted this and made it her mission to destroy Rand. This job is perfect for her.