After Twilight's use of dark magic in the Crystal Empire, she quickly becomes intrigued by it. She decides to study it a little more, but what she doesn't know is that it has a long-term effect. It slowly begins to take over Twilight's mind over time. To when she first used it, to when she became princess. It finally corrupted Twilight when her castle appeared out of thin air. She then had the urge to completely take over all of Equestria. As this "disease" slowly takes Twilight's mind, driving her mad, she assembles an army of Unicorns and Pegasi. Twilight decides she needs her army to be better equipped. She needed more than swords, she needed something more....