Her name is supposed to be pronounced as “mine” (one syllable, like the English word)
Youngest daughter of a poor family. She has a feeble body which gets a high fever if she forces it too much, it is also smaller than the average for her age. Urano Motosu reincarnated into Myne's body.
At the end of Part 2, she gets adopted by Karlsted and her name gets changed to "Rosemyne."