In a ball in Nigellus, Layla had used magic to disguise as someone else and tipped Stella that Prince Aiden's wine was laced with poison.
Panicking and not wanting to cause a scene, Stella drank it for Aiden, ready to die in his stead.
When nothing happened to her after that, Stella thought it was a crazy prank. But then one day, she no longer woke up from her sleep. It was a slow-acting poison that Layla had personally made.
Stella died a month after drinking the poison. Her body was examined by magicians but they were not able to identify Layla as the creator of the poison until several months had passed.
Alina and Aiden were already married then.
Layla had moved on her own without informing Alina. She eliminated Stella because she thought that she was no longer dear to Alina. She was loyal to the point of doing the dirty work so her mistress could live as she pleased.
