Mirajane Fanclub

About Mirajane
When Mirajane was an S-class mage, she was known as "The Demon" and had a very bad attitude with other members of the guild, usually dressed Gothic style and insulted everyone. However, due to a past incident involving the death of her younger sister, Lisanna, Mirajane somehow lost much of her magical ability and her will to fight. Given the recent event of Elfman regaining his lost abilities and Mirajane's increased confidence, Mirajane recently regained her powers.

Mirajane plays a motherly role within the guild, and is often seen running the bar at the guild hall. She has rarely been shown to be in a bad mood, and can tolerate all of the guild's eccentricities. However, there have been a couple events that have disturbed Mirajane, including her discovery of the stealing of an S-Class job by Natsu Dragneel, Happy and Lucy Heartfilia, and her later disappointment with Laxus Dreyar following the destruction of the guild building.

Mirajane is also very determined to protect her comrades, going so far as changing her appearance in order to fool the Phantom Lord Guild into thinking she was Lucy, whom they were trying to capture. Along with running a bar, Mirajane shows great talent not only in modeling, but playing guitar and singing. She is much beloved not only among the Fairy Tail members but also many outside the guild.

When she was younger, she was actually very much like Natsu as he is now and she always fought Erza Scarlet similar to how Natsu fights Gray Fullbuster. During a mission, with her younger siblings, Elfman and Lisanna, Lisanna died. It is possible that it was this incident that changed her personality to the kind and motherly one seen nowadays as she works at the guild.

Source: Fairy Tail Wikia