FROM THE POTTERMORE EDITOR: Every witch or wizard with a wand has held in his or her hands more power than we will ever know. With the right spell or potion, they can fabricate love, travel through time, change physical form and even extinguish life.
In the wrong hands, power and magic can be dark, lethal, and consuming. Lord Voldemort showed us that; he sought power so viciously that he tore apart the fabric of his soul and lost everything that made him human. He is the ultimate villain, motivated by an ice-cold desire for power and destruction.
Obviously few people could match Voldemort in general evil intent (though Bellatrix Lestrange and Dolores Umbridge indeed try), but there are certainly other characters attracted to power. Here, we’ve collected writing by J.K. Rowling on power and politics… And just for fun, poltergeists, too.