Her superpower :: she can stand along side anyone and do everything better than them. Her superweakness :: she is constantly dissatisfied and needs to find better and better people to be better than, so she can leech off of their abilities and somehow improve. She is so appealing and people want to be around her ... but her "friends" quickly feel drained of their energy and they become lethargic.
Every met someone who seems to do everything better than you? Ever wish you were them?