Jealousy. A cruel word that fit how she felt about the girl who was everything she wished to be. Millianna had been taken away from her village just as everyone else, but sadly when she was trying to get away one of the kidnappers attacked her from behind and knocked her out cold. Everything would have been fine if she woke up with her memories, but she didn't. All of her memories had disappeared and she couldn't even remember her name. Thankfully an old man who was in the same cell as her and the rest of the children named her and watched over them all.
Even though he watched over all of them, his attention always seemed to fall on Erza. Everyone always looked at Erza over her. She was a fighter and the leader that people loved to have around while Millianna was just a young girl with a cat obsession. At one point she even tried to become just like Erza, but even after that no one noticed her. No one seemed to care about her at all and that jealousy soon turned into rage and anger.
Although she knew that it was wrong to be jealous of Erza, she couldn't help it. From her point of view, no one cared about her and they wouldn't notice her even if she was gone. Or so she thought anyway. That is a tale for another time though.
Millianna grew up with this jealousy and even as an adult she feels nothing when compared to the girl she grew up with. Even now she continually compares herself with not only Erza, but Kagura as well. It isn't as bad as when she was a child though. Now she works as hard as she can to be recognized as a great mage who battled against the odds that were stacked against her. One day she knows she will surpass them and people will finally realize that she's just as great as them.