Clarissa stole a new poison that Nostradamus had been working on, and put it into a drink intended for the badly beaten Kenna. However when Lady Aylee drank it instead Clarissa again took matters into her own hands and pushes her off the 2nd floor, killing her. Aylee died on the ground with her friends around her.
Sins of the Past - (Mentioned) King Francis asks his mother, Queen Catherine, why she didn't tell him about his sister Clarissa. It turns out that Catherine hallucinated him asking it. She thought it was a vision, but she was just being poisoned.
Clarissa was a strange and almost feral young woman who hides in the shadows. Clarissa's past was a tantalizing puzzle that will reach out to change the lives around her in ways no one suspects. Clarissa is also an antagonist. During Season One, it was revealed that Clarissa is the daughter and firstborn of Catherine de' Medici Which making her a child of adultery but by royal blood bound by royal blood and because Queen Catherine is her mother she is an illegitimate princess. Clarissa was thought killed by Mary Stuart in order to save Charles' life but was later revealed to be still alive. She had not been seen since Royal Blood but made her return in Reversal of Fortune. She was reunited with Bash but shortly met her end by him in order to save Francis' life.
In Fated, Clarissa, sneaks into Nostradamus' rooms to get some of his handmade artisan poisons. She slips it in the tea meant for Kenna, but Aylee ends up drinking it instead. Since the poison is taking too long to kill her, Clarissa finally just pushes Aylee down the castle steps. Nostradamus manages to figure this out quickly and rips the sack right off Clarissa's head for the wicked thing she did in order to convince Mary of the prophecy. The viewers were not shown her face.
The king's reaction was fierce and determined: he mobilised his troops, sent the army to the rebellious areas to quell the sedition, and ordered governors to return to their positions. To isolate the renegade prince's of the blood further the administration created two super-governorships giving one to Charles, Prince of La Roche-sur-Yon and the other to Louis, Duke of Montpensier, thus divorcing their interests from those of their cousins. Heavily outnumbered Condé and Navarre decided making a stand and fighting would be pointless, and they departed their southern regional powerbase at the kings request to attend the forthcoming Estates General. 
The king's health deteriorated in November 1560. On 16 November he fainted. After only 17 months on the throne, Francis II died on 5 December 1560 in Orléans, Loiret, from an ear condition. Multiple diseases have been suggested, such as mastoiditis, meningitis, or otitis exacerbated into an abscess. Ambroise Paré, the royal surgeon, considered performing a trepanation. Some suspected Protestants of having poisoned the king, a view held by Catholics as the tensions between them and Protestants were on the rise, but this has not been proven. 781b155fdc