Harry Potter and the Prince of Slytherin

Chapter 1: In Which Plans Are Made

All of that was a lie.

"Archie Goodwin" was Regulus Black's latest fake identity. As a Metamorphmagus, Reg had grown accustomed over the past year to assuming a new form every time he went out into the Wizarding world. But now, both he and Sirius had moved into Potter Manor, and with all the guests who Harry was expecting over the summer, Reg could no longer wander around with the face of an ex-Death Eater who was officially deceased.

Reg had taken the name from a book he'd read during his time in Australia: The League of Frightened Men. His current appearance was loosely based on the Lazarus White identity he'd worn for so many years, as it was one that he felt comfortable maintaining indefinitely. It also had the benefit of being a face he'd come up with from scratch instead of being someone he'd seen in a movie or a newspaper. The metamorphmagus did change the hair and eye colors just on the off chance that someone who knew Lazarus White might be wandering around Britain, and he'd reset his age to the way it looked when he'd first moved to Australia fourteen years earlier.

"Good morning, lads! Ready for some exercise?"

"I didn't like Lockhart's creepy cheerfulness the first time, Reg," Harry deadpanned.

"Ha-HA!" the man replied with the fake "Lockhart laugh" that had grated on Harry for most of his Second Year. "It's just before dawn and we're about to go jogging, Harry," he added cheekily. "It won't get any more enjoyable if we're dour about it."

One long sweaty run later ...

After completing their run, Theo began reviewing basic Wu Xi Do katas with his friend. While Harry could perform the katas reasonably well (they were all water-based moves, and he was, after all, a Slytherin), he still felt uncomfortable and vaguely silly to be engaging in martial arts, even magical martial arts. As he'd said from the start, "any wizard who gets caught without a wand deserves what happens to him."

Reg seemed equally dubious. "So tell me again, Theo. What's the purpose of these movements?"

"They're to train the body to channel magic internally so that one can perform physical actions that are enhanced by magic. This one I'm doing now, for example, can make my body more limber and also make it easier to dodge."

"Oh?" the older wizard said while pulling out his wand. "Would you care to demonstrate?"

Theo thought about it for a moment and then nodded. He turned to face his former DADA instructor and assumed a relaxed pose. Regulus flicked his wand to send a Stinging Hex aimed at the boy's chest. Instantly, Theo twisted his body at the waist while leaning to one side, and the hex sailed by the boy, missing him by inches.

Intrigued, Regulus sent four more Stinging Hexes, each faster than the one before. Theo dodged the first three by contorting his body in increasingly twisted (and vaguely serpentine) ways, but the fourth one hit.

"Oww!" Theo hissed. "Yeah, I'm still kind of a novice, but that's the general principle."

"Still, dodging four out of five hexes is a good average," Reg said reassuringly.

"Maybe," Harry said, "but you also weren't going all out to hit him either. I mean, I've seen you duel Aurors and move faster than that. Not to mention that one time you and I dueled when I still thought you were Lockhart."

"True, but the attacks I just made were quite fast and accurate compared to what you'll see from a novice level duelist in Marseilles. More importantly, from what I've observed so far, Wu Xi Do wouldn't count as illegal magic if you used it to dodge an attack, which means it might be very useful on the dueling circuit."