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Tear Jerker: Cold Days
Remember how Mab was PISSED in Small Favor? How her very voice caused everyone to be in agony? Turns out it's because she realized that her DAUGHTER was taken by the enemies she was literally made to fight. Meaning that Maeve was going to have to die. And even though Mab could have physically done the deed, she couldn't bring herself to. Why? Because Sidheness be damned, Maeve was still her daughter and Mab still loved her. Betcha you never thought you'd feel sorry for the Queen of Air and Darkness.
Worse It took both of her daughters. One died and the other has become the Summer Lady, rendering her out of Mab's hands. Her daughter was conscripted to being an enemy, again.
The entire scene when Thomas and Harry meet again, and Thomas realizes that Harry tried to get himself killed.
To clarify: Thomas realizes that Harry was afraid of becoming a monster. In other words, Harry would rather kill himself than be what Thomas is. Ouch.
Sarissa becoming the Summer Lady. As Mab's daughter, she was (and is until the end of the book) a changeling who wanted as little to do with the Fae as possible. But Maeve's final For the Evulz moment forced the mantle onto her.
Lily dying and Fix having to watch.
The whole of the last few chapters. In order...
Maeve's speech about being The Unfavorite is made worse by the fact that, while not true, it could certainly look that way, especially if something was twisting your thoughts.
Lily takes a bullet to the head.
Mab and her regret of what she has to do.
And finally, Molly having the Winter Lady mantle forced onto her.
The extent of Titania and Lily's rage at Harry for doing what he had to do.
Titania was forced to stand aside and allow Harry to murder her daughter. And it was a VERY agonizing death of a thousand cuts that ended with Harry being forced to execute a scared little girl.
Lily had spent her entire life being abused for her beauty. Yes ... that kind of abuse. But she had clung to the choice that no one could ever take away from her: The choice to be a fae or a mortal. And the dream of having a husband and a family. And then, Dresden killed the previous Summer Lady, condemning Lily to a life of immortality with no hope of a normal family. No wonder she was so ready to kill the guy.
Even worse, her rage was mis-directed. It was Aurora who took that choice from Lily, and turned Lily into the Summer Lady, as per the Evil Plan in Summer Knight. Dresden did the best he could with what he had, and anyone who's read the series knows without a doubt that if Harry could have given Lily back her humanity, he would have done so the minute the events of Summer Knight were done and over with.
And despite her rage, her reasons to - from her point of view - hate Harry, she is, until the end, unfailingly kind to him. The meeting scene where she hugs him is pure Heartwarming.
All the implied things happening with Lily. We never get to see it firsthand, but Maeve wins her trust simply by befriending her. Above all else, Lily is lonely in an alien world that she wanted nothing to do with, and Maeve represented not only someone who understood her feelings, but could also help her stop the "evil" at Demonreach. For the entire story, she is 100% convinced that she's playing the hero's role ... just like her predecessor, Aurora. It makes the endgame a compound tragedy for her. Factor in that 1) she truly believes she's doing good, 2) the man who killed Aurora is looming over the (apparently dead) body of her closest friend and the Summer Knight, 3) that same man is the bearer of the Winter Knight's mantle, and 4) the Sidhe consider the mantles of the Summer and Winter courts to be, for all intents and purposes, titles. They shape their bearers in a certain way, given enough time. Thus, with time, there's little to distinguish one Winter Knight from another. And the previous Winter Knight had routinely raped Lily.
After the final battle, Harry asks if it was hard for Mab to kill her daughter Maeve. Mab doesn't answer. When she walks away, he asks the question again.
Mab did not turn around. When she spoke, her voice had something in it I had never heard there before and never heard again - uncertainty. Vulnerability. "I was mortal once, you know," she said, very quietly.