MINOR SPOILER
From what I’ve read from others. Athy not only inherited her raw magical ability from Claude, but was also born as a reincarnation because of Jennettes wish for time to turn back in the original novel. These combined factors lead to a very magical baby in a very normal human woman. It’s likely the power of Athy was sucking the life out of her mother, something the mother and Claude knew early in the pregnancy would likely lead to her death. Which is why Claude originally wanted an abortion.
Think Twlight how vampire baby was so strainful it took Bella’s life.
oh my, thank you for the response! that makes a lot of sense :(
does anyone remember why diana died after giving birth to athy?? was it cause of her magic or just birth complications because I don't freakin remember