Kiria

A Fifth Generation Dragon Slayer and member of Diabolos, a guild of dragon eaters. Kiria is a confident, battle-hungry individual with a habit of sticking her tongue out the side of her mouth. In combat, she tends to smile maniacally and even taunts her opponents. She appears to view battle as entertainment, shown when she attacked Natsu, Lucy, and Happy simply for the fun of it. Kiria also has a thirst for power, dedicated to hunting down and devouring dragons in order to take over their abilities, indicating a violent and sadistic nature. She also appears to be rather clever. At some point in time, Kiria devoured a Blade Dragon, which enabled her to take on their power. She then joined Diabolos, a guild exclusively comprised of Dragon Eaters, fifth generation Dragon Slayers. (Source: Fairy Tail Wiki)