Erza's Scarlet is the 6th strongest wizard in Fairy Tail. Erza is what you can call a strong hearted person who will do anything to protect her guild mates. Erza's past has helped Erza's to become the strong amazing wizard she is today. Being a slave as a child in the the Tower of Heaven (not heavenly at all) made her appreciate life and her family (FT).
Erza's uses Requip Magic that allowes her to store many armors, weapons and outfits in another place and when she requips she is a nonstop women of badass armor. Now Erza's has a lot of requips. She has Heavens Wheel, Japanese Cloth, Fire Empress Armor, Sea Empress Armor, Lighting Empress Armor, Arma dura, Adamatine Armor, Purgatory Armor, Robe of Yuen, Black Wing Armor, Flight Armor, Morning Star Armor, Giants Armor, and Farewell Armor. (Sadly I do not have the last 4 in the pictures) Erza is an amazing Fairy Tail wizard and there's no wonder why she's called Queen of the Fairies.
In the Tartaros Arc. Erza comes face to face with the demon Kyouka who likes to punish and torture people. Kyouka also like to make humans into demons. She was in the process of creating two new demon one successfully completed which was Minerva from Sabertooth and well they also tried to make Mira into a demon but the joke was on them because she already was one to begin with. Erza tortured by Kyouka after being drugged by the backstabbing councilman because she didn't know where Jellal was located (even if she knew she wouldn't say anything) When Erza finally got free of course a battle was inevitable. Kyouka had to go somewhere else so of course she left her to fight with her old rival Minerva. Thanks to Erza's amazing heart and strong words made Minerva realize she is fight the wrong person and to go back to her guild that she knew someone was missing her making Minerva change to the good side. Finally today I will see Kyouka and Erza's duke it out like the strong Fairy Tail wizard she is making it the last demon from the Tartaros guild. Can't wait!