So, by now we know that Mab was linked to Merlin, and that she loved him. It probably means, following the Arthurian legends, that she was Niniane/Viviane when she was a mortal, and that she is somehow responsible for Merlin's death/imprisonment in Demonreach.

But I wonder, as it's been established that Ebenezar and Harry are descendants of Merlin, who was the woman part of the lineage? For me, it's starting to look a lot like Mab could be Harry's ancestor. She's been protecting Harry for a while now, preparing him for what's to come in her tough love way, and has been very patient with him. Remember, we're talking about Mab, and she hates insolence against herself or her Court. But somehow, at the end of BG, she seems really happy that he intends to rebel against her. It almost looked like she was proud of him. And at least the last two or three books have been insisting on the parallels between Mab and Harry, what it means to become a monster, the sacrifices one has to make in order to save the people around them.

BG tells us that Mab is basically a general hardened by war, and that she recognizes Harry as a fellow soldier who is starting to understand what it takes to fight this war. But what if it was something like a mother/grandmother who was happy that her offspring finally took her lessons to heart? There's also the scene with Mother Winter trying to kill Harry, and afterwards Mother Summer basically told us that she's shown Harry respect/love in her own way. And what about the Blackstaff, which is starting to look more and more like Mother Winter's walking cane? Wouldn't it make sense that it somewhat stayed in the family? Ethniu says about Eb that he's a child playing with an adult toy, but usually, kids do that with objects from their own family.

Of course, I think people will point out that Mab had sex with Harry in front of all the Fae. First, even Harry said there was nothing really sexual about it, and that it was more about trying to survive a hurricane (or something like that). And second, we've seen that Mab is ready to do whatever is necessary to achieve her means: having sex with Harry was probably the only way to give him the Winter Knight mantle, so she had no choice, and also, what better way to dismiss any way this theory could be true to her enemies than doing that?

Mab has been protecting Harry for a long time, often from himself, with Harry taking that as unfair pressure from someone alien who wanted him to become something he didn't want. Sounds a lot to me like a child not wanting to follow what their parents want for them.