| Spoiler warning! This article contains plot details from the latest book. |
Glimmer is a former Neverseen member and a Flasher. In Legacy, she was the one who tied bonds onto Tam's wrists to let the Neverseen control him. She is described by Sophie as a girl (most likely not an adult).
Glimmer tries to make friends with Tam while he is with the Neverseen, but he is determined to ignore her.
At the battle in Loamnore, she breaks Tam's bonds so he can help Sophie and her friends, and offers assistance to Sophie.
Later, after the battle, she's invited by Tam to live with Tam and Linh. However, she refuses to tell people her real identity and show her face, keeping herself hidden underneath her cloak.
Glimmer's Identity Theories
Although a long shot, some fans believe that Glimmer may be Mai Song, Tam and Linh's mom. First off, both Glimmer and Mai have long, straight ebony hair, as do Tam and Linh. It is said in the Tam Short Story from Tam's POV that Glimmer sounds like Linh when she speaks. She also showed that she cares about Tam during his stay with the Neverseen, often checking on him and trying to become his friend. Mai Song/Glimmer was likely recruited to the Neverseen by Lady Gisela. Lord Cassius briefly mentioned that he knew Quan Song (Mai's husband) and they sometimes met up. It would make sense for Lady Gisela and Mai to then hang out together, and when Lady Gisela noticed how powerful a Flasher Mai was, she may have invited her to join the order. Mai also seemed to regret letting Tam and Linh get banished, so she may have been angry at the Council, and joining the Neverseen might have been her way at getting back at them. She could have been mad at them for not silencing the prejudice on multiple births, too, since she maybe felt pressure to say that her children weren't twins (not to say that what she did was right).
Additionally, this would mean that Mai Song is a Flasher, while Tam is a Shade, and the two abilities may have the same core, similar to Empaths and Enhancers. This would explain why Tam is a Shade. Glimmer is said to be an extremely powerful Flasher, and both her children are also very talented ability-wise.
Lastly, Glimmer changed sides in Legacy, helping Sophie and her friends in Loanmore. Once the Neverseen had lost the battle, she left the Neverseen, coming back to the Lost Cities with Sophie's friends. Tam thought Glimmer should come live with him and Linh, but Linh disagreed since Glimmer would not show her face, keeping her cloak's hood up. This is probably because she was afraid of the betrayal her family would feel if she revealed who she was.
First off, they are both Flashers, and they both have long black hair. Luzia is mentioned at the beginning of Legacy, she was apparently "waiting to be sentenced" and we hear nothing more of her. She has always been cunning and is known to keep secrets. She is also known to be a powerful Flasher and would thus be able to make the etherine bonds that Lady Gisela had put on Tam. She has worked with Vespera before, so maybe Vespera/Lady Gisela recruited her. She could have joined the Neverseen for any number of reasons, but after the "Scandal at Everglen" she is probably bitter towards: the Councillors for her tribunal and she is maybe even a little bitter towards Sophie and her friends for exposing the hive at the Celestial Festival (even though that was Vespera, Lady Gisela "has proven time and time again to be a master of mind games and manipulation".) She has also proven to kinda "change sides" from working with Vespera to helping Sophie save Wynn and Luna. She might not want to show her face because she betrayed Sophie and her friends by not telling them about the troll hive at Everglen. (Happy Shadow Thoughts 101)