Jada is the alter-ego of Danielle Megan "The Mega" O'Malley, better known as "Dani". Cold and calculating to Dani's fiery and reckless demeanor, Jada is the persona that Dani takes on only during times of extreme duress. Once Jada takes over, however, she remains in control of Dani's body and mind until (a) she chooses to relinquish control over Dani, or (b) Dani fights her way back to the surface, and reclaims her body and mind by force.
At the end of Burned, Jada is in full control of Dani's body and mind, and is a main character in the continuing storyline.
Jada appears to be 19 or 20 years old. She has ice cold green eyes, that view everything coldly and clinically. She has long, curly red hair that she meticulously straightens, and keeps in a long ponytail down her back. Roughly 5'10" in height with a lean build. She prefers tight, low-necklined shirts, tight jeans, and combat boots. Sexy, yet practical.
There are currently two theories for how Jada came into existence. The first theory is that due to the childhood neglect of her mother, whom often left her caged for days on end without food or water, Dani ended up suffering from Dissociative Identity Disorder, meaning that her mind created a second, fully-functioning personality that was better equipped to deal with the neglect.
The second theory for Jada's formation is that Rowena experimented on Dani from a very young age in an attempt to turn her into a living weapon, and that it was from those experiments that Jada was created. Ryodan confirms that Rowena kept detailed journals of the experiments she performed on Dani as a child, possibly even as an infant. It isn't outright said whether Rowena's experiments were the root cause of Jada's formation, or if Rowena's experiments only served to worsen Dani's pre-existing mental condition.
Until recently, Jada only appeared under specific circumstances, and then Dani retook control. Said circumstances include but are not limited to Rowena coaxing Jada to come out and lead Alina Lane to her Unseelie murderers, and times when Dani was on the brink of death.
However, after MacKayla accidentally chased Dani into the Hall of All Days (the Grand Central Station-equivalent for the Unseelie silvers), Dani was lost for nearly a month. A month in the human world is five and a half years in whichever worlds Dani became lost in. Jada tells Ryodan that Dani held on to the false hopes that he would come to save her, and it was when she lost her faith in Ryodan that Dani gave in and gave Jada the reigns. Jada has been in control ever since, and doesn't plan on giving up control anytime soon.
Upon seeing Jada for the first time since her return from the silvers, Ryodan is the only one to recognize Jada as Dani. He is furious at Jada for not returning to her cave and allowing Dani to come out, and refuses to believe Jada when she claims that Dani is dead. It is very clear that while Ryodan and Jada outwardly dislike each other, Jada at the very least respects Ryodan and is also attracted to him, revealed by a kiss they share in his office.
When Ryodan tells Jada that Dani could have anticipated the movements of the Crimson Hag when Jada couldn't, Jada is deeply injured by his accusation, and even goes so far as to ask MacKayla if she agreed with Ryodan's observation.
When Dani is in control of her own body and mind, she has little to no memory of Jada's words or actions. She has no idea that Jada is a fully-functioning person, with her own desires, ideas, skills, etc. She is aware that there is a place inside her she can go when she needs help, which she refers to as a "dark cave", similar to the way MacKayla refers to her "glassy lake". Dani only goes into that dark cave when she feels like she can't survive on her own.